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Elements
How many elements are there?

What should you know about a chemical element?

What is the name of the chemical element and its derivatives that you are manufacturing?

What do you understand by derivatives of an element?

Is there a difference between a compound and an alloy?

What is the difference between a compound and an alloy?

What are various element groups?

What are the properties of various element groups?

How many elements are in each element groups?

What are all the elements?

How is the element extracted?

What are properties of the element?

What are the uses of the element?

What are various organic molecules?

How do you verify the density of a material?

Are there other better classifications that give better insight?

How about Qureshi's classification of elements?

What is an element?

How many elements are there?

What is the difference between atoms and elements?

What is the difference between a compound and a molecule?

What is an atom?

What are atoms made of?

What is the simplest way of explaining what atoms, elements, compounds and mixtures are?

What elements are present in the human body?

What elements are liquids at room temperature?

Where can I find information about elements on the Web?

What elements are liquids at room temperature?

Why is potassium necessary in the diet?

What is the most abundant element?

Why is mercury a liquid at STP?

What is the most abundant element?

Where can I find information about elements on the Web?

What is density?

What are Mixtures and Solutions?

What is Specific Gravity?

What is an isotope?

How do you know if an isotope of an element is radioactive?

What are all the elements?

What is atomic number?

What determines average atomic weight?

What is an atom?

What are atoms made of?

What is the difference between atoms and elements?

What is an atom? What are atoms made of?

What is the Periodic Table of The Elements?

What elements are present in the human body?

What elements are liquids at room temperature?

What is the most abundant element? What is a mineral?

What is a rock?

Where do metals come from?

Why is potassium necessary in the diet?

What is density?

What are Chemical Properties and Changes?

What are Mixtures and Solutions?

What is Specific Gravity?

What does a refractometer do?

What do you know about the chemical element aluminum?

What should you know about this element?

What are the properties of this element?

How is the pure aluminum element manufactured?

What common shapes of the pure aluminum element are manufactured?

How is this element extracted?

How is this element recycled?

What are the compounds of this element?

What are the alloys of this element?

What is the history of this element?

What are the health concerns of this element?

What effects does this element have on plants?

What are the uses of this element?

What products are manufactured from this chemical element or its derivatives?

What are the alloys relevant to this element?

What are names and details of the chemical elements in alphabetical order?

What should you know about a chemical element?

Can you elaborate on a chemical element in 100 questions and answers?

What is the name of this chemical element?

What is the symbol of this chemical element?

What is the atomic number of this chemical element?

The atomic number and serial number are usually the same. What is the atomic weight of this chemical element?

What is the standard state of this chemical element?

Is it solid, liquid, or gas?

What is the standard CAS Registry ID of this chemical element?

What is the group of this chemical element?

What is the group name of this chemical element?

What is the period of this chemical element?

What is the block of this chemical element?

What is the color of this chemical element?

Is this chemical element metallic of non-metallic?

What are uses of this chemical element naturally?

What does this chemical element react with?

How do you calculate the atomic number?

What products are made from this chemical element?


Atomic Structure

1 What is an Atom?
2 Which Particles are found in the Nucleus?
3 What is the charge on an Electron?
4 What is the charge on a Neutron?
5 Does a Proton have more mass than a Neutron?
6 Does a Proton have more mass than an Electron?
7 What is the Atomic Number?
8 What is an Isotope?
9 What is the maximum number of Electrons in each Shell?


Ionic Bonding

10 How does an Atom become an Ion?
11 Write the Balanced Equation for the reaction between Sodium and Chlorine.
12 Draw a Dot and Cross diagram for the reaction between Sodium and Chlorine.
13 What is an Ionic Bond?
14 What type of Structure do Ionic Compounds form?
15 A metal in group 1 will form what type of Ion?
16 A non-metal in group 7 will form what type of Ion?
17 What is the connection between an Ion and a Noble Gas?
18 What is the name of the Compound made from Lithium and Chlorine?
19 What is the formula of Magnesium Oxide?
20 What is the formula of Aluminium Oxide?
21 Give two Properties of Ionic Compounds?
22 What does the state symbol aq mean?
21 What is the formula of Calcium Carbonate?


Covalent Bonding

22 What does Covalent mean?
23 How many Electrons are there in a Single Covalent Bond?
24 When is a Compound called a Molecule?
25 Draw a Dot and Cross diagram for a Chlorine Molecule.
26 Draw a Dot and Cross diagram for an Ammonia Molecule.
27 Draw a Dot and Cross diagram for a Water Molecule.
28 Are Covalent Bonds Strong or Weak?
29 Do Molecular Substances Conduct Electricity?


Giant Molecules

30 What is a Giant Molecule?
31 Give one Example of a Giant Molecule?
32 What is an Allotrope?
33 Why does Graphite Conduct Electricity?
34 Give two Properties of a Giant Molecule?


Metallic Bonding

35 What type of Structure do Metals Form?
36 What are Free Electrons?
37 Give two Properties of Metals?


The Periodic Table

1 Why did Dmitri Mendeleev leave gaps in his Periodic Table?
2 What is a Column called?
3 What is a Row called?
4 Where do you find Non-Metals in the Periodic Table?
5 What is important about the Group Number of an Element?
6 What is the Electron Structure of Potassium?


The Alkali Metals

7 What is the Group Number of the Alkali Metals?
8 Why are the Alkali Metals stored under oil?
9 Give two Properties of the Alkali Metals?
10 Going down the Group, do the Alkali Metals become More Reactive?
11 Write the Word Equation for the reaction when Potassium burns in Air.
12 What Colour is the Flame from Potassium?
13 Write the Balanced Equation for the reaction when Potassium burns in Air
. 14 Write the Balanced Equation for the reaction between Sodium and Water.
15 Write two things you would See in the reaction between Sodium and Water.
16 Write the Balanced Equation for the reaction between Lithium and Chlorine.
17 Give one Property of an Alkali Metal Compound?
18 Give one Use of Sodium Chloride?
19 Give one Use of Sodium Carbonate?


Electrolysis of Sodium Chloride in Water

20 What is Brine?
21 Which Gas is given off at the Cathode?
22 Which Gas is given off at the Anode?
23 Give the Ionic Equation for the Gas given off at the Anode.
24 Why don't you get Sodium Metal at the Cathode?
27 What Substance is left in Solution after Electrolysis?
28 Give one Use of this Substance?


The Transition Metals

'' 29 Where do you find the Transition Metals in the Periodic Table?
30 What is their Group Number?
31 Do the Transition Metals Conduct Electricity?
32 Do the Transition Metals form Coloured Compounds?
33 Give one Use of Copper?
34 Give one Example of a Transition Metal Used as a Catalyst.


The Halogens

35 What is the Group Number of the Halogens?
36 What does Diatomic mean?
37 What Colour is Chlorine?
38 What Colour is Bromine?
39 Is Iodine a Liquid?
40 Going down the Group, do the Halogens become More Reactive?
41 Going down the Group, do the Halogens have a Higher Boiling Point?
42 Write the Balanced Equation for the reaction between Aluminium and Chlorine.
43 Write the Balanced Equation for the reaction of Chlorine with Potassium Iodide.
44 Write the Ionic Equation for the reaction of Chlorine with Potassium Iodide.
45 Give one Use of Fluoride?
46 Give one Use of Chlorine?
47 Give one Use of Bromide?
48 What does Hydrogen Chloride make when it is Dissolved in Water?
49 How is Hydrogen Chloride Safely Dissolved in Water?


The Noble Gases

50 What is the Group Number of the Noble Gases?
51 What does Monatomic mean?
52 Going down the Group, do the Noble Gases have a Higher Boiling Point?
53 Give one Use of Helium?
54 Give one Use of Neon?
55 Give one Use of Argon?

What Is a Chemical?
What Is a Chemical Element?


How many elements are there?

As of August 21, 2012, scientists know of 118 different elements.

http://www.qureshiuniversity.org/elements1.html

What is an Element (in terms of Chemistry) ?
www.qureshiuniversity.com/elementsdefinition.html

What should you know about a chemical element?
You should be able to elaborate on chemical elements under at least 100 different headings.

Atomic number
Atomic mass and atomic weight
Allotropes
Abundance
Alloys
Appearance
Atomic Radius (pm)
Atomic Volume (cc/mol)
Abundance of elements (Earth's crust)
Abundance of elements (oceans)
Abundance of elements (meteorites)
Abundance of elements (stream)
Abundance of elements (sun)
Abundance of elements (Universe)
Abundances in humans
Accurate mass of the isotopes
Alternate Names (Name in Other Languages)
Biological role
Block in periodic table
Boiling point
Bond enthalpy (diatomics)
Bulk modulus
Covalent Radius
Chloride(s)
Crystal structures
Chemical symbols
Compounds
Covalent radius 2008 values
Covalent radius
Critical temperature
Crystal structure
Chemical Name
Chemical Formula
CAS Registry Number
Density (g/cc)
Description
Discovery
Debye Temperature (K)
Extraction
Effect on plants
Effective nuclear charge
Electrical resistivity
Electron affinity
Electron binding energies
Electronegativities
Electronic configuration
Element bond length
Enthalpy of atomization
Enthalpy of fusion
Enthalpy of vaporization
Examples of compounds
Element Classification: Transition Metal
Evaporation Heat (kJ/mol)
Electrical Resistivity (20°C)
Emergency Response Guide Number
Fusion Heat (kJ/mol)
First Ionizing Energy (kJ/mol)
Group numbers
Hardness _ Brinell
Hardness _ Vickers
Hardness _ Mohs
Hydride(s)
History of the element
Health concerns
Isotopes
Ionic atom_sizes (Shannon)
Ionic radius (Pauling)
Ionic radius (Pauling) of monocation
ionisation energies
Isolation
Isotope abundances
Isotope nuclear spins
Isotope nominal mass
Isotope nuclear magnetic moment
Lattice Structure
Lattice Constant (Å)
Lattice energies
Linear expansion coefficient
Metal Terms
Melting and boiling points
Meaning of name
Melting point
Mineralogical hardness
Molar volume
Molecular Weight
Magnetic Ordering
Names and symbols
NMR frequency
NMR isotopes
NMR magnetogyric ratio
NMR quadrupole moment
NMR receptivity
NMR relative sensitivity
Nomenclature and symbols
Occurrence and origin on Earth
Oxide(s)
Oxidation States
Properties
Recycling
Production and refinement
Poisson Ratio
Pauling Negativity Number
Poisson's ratio
Properties of some compounds
Radius metallic (12)
Radioactive isotopes
Reactions of elements
Reduction potential M(aq)
Reflectivity
Refractive index
Registry number
Rigidity modulus
Related Hazardous Material Name
Reaction with Air
Reaction with 6M HCl
Reaction with 15M HNO3
Standard atomic weight
Standard state
Solid, liquid, or gas
Superconductivity temperature
Symbol
Sources
Speed of Sound
Specific Heat
Shear Modulus
Stability
Term symbol
Thermal conductivity
Thermal Expansion (25°C)
Thermodynamic properties
Uses
Valence orbital R(max)
Van der Waals radius
Velocity of sound
X_ray crystal structure
Young's modulus
What is the name of the chemical element and its derivatives that you are manufacturing?
What are all the elements?

Alphabetical list of Elements
Aluminium
Actinium
Americium
Antimony
Argon
Arsenic
Astatine
Barium
Berkelium
Beryllium
Bismuth
Bohrium
Boron
Bromine
Cadmium
Cesium
Calcium
Californium
Carbon
Cerium
Chlorine
Chromium
Cobalt
Copper
Curium
Darmstadtium
Dubnium
Dysprosium
Einsteinium
Erbium
Europium
Fermium
Fluorine
Francium
Gadolinium
Gallium
Germanium
Gold
Hafnium
Hassium
Helium
Holmium
Hydrogen
Indium
Iodine
Iridium
Iron
Krypton
Lanthanum
Lawrencium
Lead
Lithium
Lutetium
Magnesium
Manganese
Meitnerium
Mendelevium
Mercury
Molybdenum
Neodymium
Neon
Neptunium
Nickel
Niobium
Nitrogen
Nobelium
Osmium
Oxygen
Palladium
Phosphorus
Platinum
Plutonium
Polonium
Potassium
Praseodymium
Promethium
Protactinium
Radium
Radon
Rhenium
Rhodium
Roentgenium
Rubidium
Ruthenium
Rutherfordium
Samarium
Scandium
Seaborgium
Selenium
Silicon
Silver
Sodium
Strontium
Sulfur
Tantalum
Technetium
Tellurium
Terbium
Thallium
Thorium
Thulium
Tin
Titanium
Tungsten
Ununbium
Ununhexium
Ununoctium
Ununpentium
Ununquadium
Ununseptium
Ununtrium
Uranium
Vanadium
Xenon
Ytterbium
Yttrium
Zinc
Zirconium

Here are further guidelines.
What are all the elements?

Atomic Number

Symbol

Name

Average Atomic Weight
(u)

1

H

Hydrogen

1.00794

2

He

Helium

4.002602

3

Li

Lithium

6.941

4

Be

Beryllium

9.012182

5

B

Boron

10.811

6

C

Carbon

12.0107

7

N

Nitrogen

14.0067

8

O

Oxygen

15.9994

9

F

Fluorine

18.9984032

10

Ne

Neon

20.1797

11

Na

Sodium

22.989770

12

Mg

Magnesium

24.3050

13

Al

Aluminium

26.981538

14

Si

Silicon

28.0855

15

P

Phosphorus

30.973761

16

S

Sulfur

32.065

17

Cl

Chlorine

35.453

18

Ar

Argon

39.948

19

K

Potassium

39.0983

20

Ca

Calcium

40.078

21

Sc

Scandium

44.955910

22

Ti

Titanium

47.867

23

V

Vanadium

50.9415

24

Cr

Chromium

51.9961

25

Mn

Manganese

54.938049

26

Fe

Iron

55.845

27

Co

Cobalt

58.933200

28

Ni

Nickel

58.6934

29

Cu

Copper

63.546

30

Zn

Zinc

65.39

31

Ga

Gallium

69.723

32

Ge

Germanium

72.64

33

As

Arsenic

74.92160

34

Se

Selenium

78.96

35

Br

Bromine

79.904

36

Kr

Krypton

83.80

37

Rb

Rubidium

85.4678

38

Sr

Strontium

87.62

39

Y

Yttrium

88.90585

40

Zr

Zirconium

91.224

41

Nb

Niobium

92.90638

42

Mo

Molybdenum

95.94

43

Tc

Technetium

[98]

44

Ru

Ruthenium

101.07

45

Rh

Rhodium

102.90550

46

Pd

Palladium

106.42

47

Ag

Silver

107.8682

48

Cd

Cadmium

112.411

49

In

Indium

114.818

50

Sn

Tin

118.710

51

Sb

Antimony

121.760

52

Te

Tellurium

127.60

53

I

Iodine

126.90447

54

Xe

Xenon

131.293

55

Cs

Caesium

132.90545

56

Ba

Barium

137.327

57

La

Lanthanum

138.9055

58

Ce

Cerium

140.116

59

Pr

Praseodymium

140.90765

60

Nd

Neodymium

144.24

61

Pm

Promethium

[145]

62

Sm

Samarium

150.36

63

Eu

Europium

151.964

64

Gd

Gadolinium

157.25

65

Tb

Terbium

158.92534

66

Dy

Dysprosium

162.50

67

Ho

Holmium

164.93032

68

Er

Erbium

167.259

69

Tm

Thulium

168.93421

70

Yb

Ytterbium

173.04

71

Lu

Lutetium

174.967

72

Hf

Hafnium

178.49

73

Ta

Tantalum

180.9479

74

W

Tungsten

183.84

75

Re

Rhenium

186.207

76

Os

Osmium

190.23

77

Ir

Iridium

192.217

78

Pt

Platinum

195.078

79

Au

Gold

196.96655

80

Hg

Mercury

200.59

81

Tl

Thallium

204.3833

82

Pb

Lead

207.2

83

Bi

Bismuth

208.98038

84

Po

Polonium

[209]

85

At

Astatine

[210]

86

Rn

Radon

[222]

87

Fr

Francium

[223]

88

Ra

Radium

[226]

89

Ac

Actinium

[227]

90

Th

Thorium

232.0381

91

Pa

Protactinium

231.03588

92

U

Uranium

238.02891

93

Np

Neptunium

[237]

94

Pu

Plutonium

[244]

95

Am

Americium

[243]

96

Cm

Curium

[247]

97

Bk

Berkelium

[247]

98

Cf

Californium

[251]

99

Es

Einsteinium

[252]

100

Fm

Fermium

[257]

101

Md

Mendelevium

[258]

102

No

Nobelium

[259]

103

Lr

Lawrencium

[262]

104

Rf

Rutherfordium

[261]

105

Db

Dubnium

[262]

106

Sg

Seaborgium

[266]

107

Bh

Bohrium

[264]

108

Hs

Hassium

[277]

109

Mt

Meitnerium

[268]

110

Uun

Ununnilium

[281]

111

Uuu

Unununium

[272]

112

Uub

Ununbium

[285]

114

Uuq

Ununquadium

[289]

116

Uuh

Ununhexium

unknown

118

Uuo

Ununoctium

unknown

Elements by Atomic Number Alphabetical list of Elements
Elements Atomic Number Name
 of Elements
Symbol
of Elements
Name
 of Elements
Elements Symbol & Atomic Number

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118

Hydrogen
Helium
Lithium
Beryllium
Boron
Carbon
Nitrogen
Oxygen
Fluorine
Neon
Sodium
Magnesium
Aluminium
Silicon
Phosphorus
Sulfur
Chlorine
Argon
Potassium
Calcium
Scandium
Titanium
Vanadium
Chromium
Manganese
Iron
Cobalt
Nickel
Copper
Zinc
Gallium
Germanium
Arsenic
Selenium
Bromine
Krypton
Rubidium
Strontium
Yttrium
Zirconium
Niobium
Molybdenum
Technetium
Ruthenium
Rhodium
Palladium
Silver
Cadmium
Indium
Tin
Antimony
Tellurium
Iodine
Xenon
Caesium
Barium
Lanthanum
Cerium
Praseodymium
Neodymium
Promethium
Samarium
Europium
Gadolinium
Terbium
Dysprosium
Holmium
Erbium
Thulium
Ytterbium
Lutetium
Hafnium
Tantalum
Tungsten
Rhenium
Osmium
Iridium
Platinum
Gold
Mercury
Thallium
Lead
Bismuth
Polonium
Astatine
Radon
Francium
Radium
Actinium
Thorium
Protactinium
Uranium
Neptunium
Plutonium
Americium
Curium
Berkelium
Californium
Einsteinium
Fermium
Mendelevium
Nobelium
Lawrencium
Rutherfordium
Dubnium
Seaborgium
Bohrium
Hassium
Meitnerium
Darmstadtium
Roentgenium
Ununbium
Ununtrium
Ununquadium
Ununpentium
Ununhexium
Ununseptium
Ununoctium
H
He
Li
Be
B
C
N
O
F
Ne
Na
Mg
Al
Si
P
S
Cl   
Ar
K
Ca 
Sc
Ti 
V
Cr
Mn
Fe
Co
Ni
Cu
Zn
Ga
Ge       
As
Se
Br 
Kr
Rb
Sr
Y
Zr
Nb
Mo
Tc
Ru
Rh
Pd
Ag
Cd
In
Sn
Sb
Te
I
Xe
Cs
Ba
La
Ce
Pr
Nd 
Pm
Sm
Eu
Gd
Tb       
Dy
Ho
Er
Tm
Yb
Lu
Hf
Ta
W
Re
Os
Ir
Pt
Au 
Hg
Tl 
Pb
Bi
Po
At
Rn
Fr
Ra
Ac
Th
Pa
U
Np 
Pu
Am
Cm
Bk
Cf 
Es
Fm
Md
No 
Lr
Rf
Db
Sg
Bh
Hs
Mt          
Ds
Rg
Uub
Uut
Uuq
Uup
Uuh
Uus
Uuo     
Actinium
Aluminium
Americium
Antimony
Argon
Arsenic
Astatine
Barium
Berkelium 
Beryllium
Bismuth
Bohrium
Boron
Bromine
Cadmium
Cesium
Calcium
Californium
Carbon
Cerium
Chlorine
Chromium
Cobalt
Copper
Curium 
Darmstadtium
Dubnium
Dysprosium
Einsteinium 
Erbium
Europium
Fermium
Fluorine
Francium
Gadolinium
Gallium
Germanium
Gold
Hafnium
Hassium
Helium
Holmium
Hydrogen
Indium
Iodine
Iridium
Iron
Krypton
Lanthanum
Lawrencium
Lead
Lithium
Lutetium 
Magnesium
Manganese
Meitnerium
Mendelevium
Mercury
Molybdenum
Neodymium
Neon
Neptunium
Nickel 
Niobium
Nitrogen
Nobelium
Osmium
Oxygen 
Palladium
Phosphorus
Platinum
Plutonium
Polonium
Potassium 
Praseodymium
Promethium
Protactinium 
Radium 
Radon
Rhenium
Rhodium
Roentgenium
Rubidium 
Ruthenium
Rutherfordium
Samarium 
Scandium
Seaborgium 
Selenium
Silicon 
Silver
Sodium 
Strontium
Sulfur
Tantalum
Technetium
Tellurium
Terbium
Thallium
Thorium
Thulium
Tin
Titanium
Tungsten
Ununbium
Ununhexium
Ununoctium
Ununpentium
Ununquadium 
Ununseptium
Ununtrium
Uranium
Vanadium
Xenon 
Ytterbium
Yttrium
Zinc
Zirconium
Ac - 89
Al - 13
Am - 95
Sb - 51
Ar - 18
As - 33
At - 85
Ba - 56
Bk - 97
Be - 4
Bi - 83
Bh - 107
B - 5
Br - 35
Cd - 48
Cs - 55
Ca - 20
Cf - 98 
C - 6
Ce - 58
Cl - 17
Cr - 24
Co - 27
Cu - 29
Cm - 96
Ds - 110
Db - 105
Dy - 66
Es - 99
Er - 68
Eu - 63
Fm - 100
F - 9
Fr - 87
Gd - 64
Ga - 31
Ge - 32
Au - 79
Hf - 72
Hs - 108
He - 2
Ho – 67
H - 1
In - 49
I - 53
Ir - 77 
Fe - 26
Kr - 36 
La - 57
Lr - 103
Pb - 82
Li - 3
Lu - 71
Mg - 12
Mn - 25
Mt - 109
Md - 101
Hg - 80
Mo - 42
Nd - 60
Ne - 10
Np - 93
Ni - 28
Nb - 41
N - 7
No - 102
Os - 76
O - 8
Pd - 46
P - 15
Pt - 78
Pu - 94
Po - 84
K - 19 
Pr - 59
Pm - 61
Pa - 91
Ra - 88
Rn - 86
Re - 75
Rh - 45
Rg - 111
Rb - 37
Ru - 44
Rf - 104
Sm - 62
Sc - 21
Sg - 106 
Se - 34
Si - 14
Ag - 47
Na - 11
Sr - 38
S - 16
Ta - 73
Tc - 43
Te - 52
Tb - 65
Tl - 81
Th - 90
Tm - 69
Sn - 50
Ti - 22
W - 74
Uub - 112
Uuh - 116
Uuo - 118
Uup - 115
Uuq - 114
Uus - 117
Uut - 113
U - 92
V - 23
Xe - 54
Yb - 70
Y - 39
Zn - 30 
Zr - 40        
What do you understand by derivatives of an element?

Derivatives can be compounds, alloys, other combinations.

Is there a difference between a compound and an alloy?

Yes, there is.

What is the difference between a compound and an alloy?

A compound is a chemical substance that consists of two or more elements that together form a molecule.

An alloy mixture contains two or more metallic elements or metallic and non-metallic elements that are usually fused together or dissolving into each other when molten.

What are various element groups?
Element Groups:
    Alkali Metals
    Alkaline Earth Metals
    Transition Metals
    Other Metals
    Metalloids
    Non-Metals
    Halogens
    Noble Gases
    Rare Earth Elements
What is the difference between atoms and elements?

element - a basic substance that can't be simplified (hydrogen, oxygen, gold, etc...)

atom - the smallest amount of an element

molecule - two or more atoms that are chemically joined together (H2, O2, H2O, etc...)

compound - a molecule that contains more than one element (H2O, C6H12O6, etc...)

What is an atom? What are atoms made of?

Atoms are the basic building blocks of ordinary matter. Atoms can join together to form molecules, which in turn form most of the objects around you.

Atoms are composed of particles called protons, electrons and neutrons. Protons carry a positive electrical charge, electrons carry a negative electrical charge and neutrons carry no electrical charge at all. The protons and neutrons cluster together in the central part of the atom, called the nucleus, and the electrons 'orbit' the nucleus. A particular atom will have the same number of protons and electrons and most atoms have at least as many neutrons as protons.

What is the Periodic Table of The Elements?

The periodic table is the most important chemistry reference there is. It arranges all the known elements in an informative array. Elements are arranged left to right and top to bottom in order of increasing atomic number. Order generally coincides with increasing atomic mass.

The different rows of elements are called periods. The period number of an element signifies the highest energy level an electron in that element occupies (in the unexcited state). The number of electrons in a period increases as one traverses down the periodic table; therefore, as the energy level of the atom increases, the number of energy sub-levels per energy level increases. Using the data in the table scientists, students, and others that are familiar with the periodic table can extract information concerning individual elements. For instance, a scientist can use carbon's atomic mass to determine how many carbon atoms there are in a 1 kilogram block of carbon.

People also gain information from the periodic table by looking at how it is put together. By examining an element's position on the periodic table, one can infer the electron configuration. Elements that lie in the same column on the periodic table (called a "group") have identical valance electron configurations and consequently behave in a similar fashion chemically. For instance, all the group 18 elements are inert gases. The periodic table contains an enormous amount of important information. People familiar with how the table is put together can quickly determine a significant amount of information about an element, even if they have never heard of it.



What elements are present in the human body?

Living cells contain anywhere from 65 to 90% water by weight, so it's no surprise that most of the body's mass is oxygen. Carbon, the basic building block of organic compounds, takes second place. Together, the top six body elements - oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus - account for about 99% of the body's mass.

What elements are liquids at room temperature?

Two elements are liquid at room temperature (298 K):

Bromine (Br)
Mercury (Hg)

What is the most abundant element?

Hydrogen is more plentiful than any other element, making up about 3/4 the mass of the universe. . Helium is second, making up almost all of the remaining 25%. Oxygen is a distant third.

On earth, oxygen is the most common element, making up about 47% of the earth's mass. Silicon is second, making up 28%, followed by aluminum (8%), iron (5%), magnesium (2%), calcium (4%), sodium (3%), and potassium (3%). All of the remaining elements together make up less than 1% of the earth's mass.

What is a mineral?

A mineral is (generally) an inorganic, naturally occurring, organized crystalline structure composed of a single chemical compound or element.

What is a rock?

A rock is (generally) a natural solid composed of multiple crystals of one or more minerals. Although many rocks contain visible crystals of individual minerals, a rock itself does not have an overall crystalline structure.

Where do metals come from?

Most pure metals, like aluminium, silver and copper, come from the Earth�s crust. They are found in ores � solid materials called minerals, usually occurring in rock, from which the pure metal has to be extracted. The properties of pure metals can be improved by mixing them with other metals to make alloys.

Metals are often divided into:
ferrous metals, which have iron in them (for example mild steel, carbon steel and cast iron) non-ferrous metals, which don�t have iron in them (for example copper, aluminium, tin and lead).

Elements

Why is potassium necessary in the diet?

Hydrogen and oxygen

How can pure hydrogen gas be prepared and detected? What is an Atom?

What is density?

Density is a physical property of matter, as each element and compound has a unique density associated with it. Density defined in a qualitative manner as the measure of the relative "heaviness" of objects with a constant volume.

For example: A rock is obviously more dense than a crumpled piece of paper of the same size. A styrofoam cup is less dense than a ceramic cup.

Density may also refer to how closely "packed" or "crowded" the material appears to be - again refer to the styrofoam vs. ceramic cup. Density Comparison to Water: In chemistry, the density of many substances is compared to the density of water. Does an object float on water or sink in the water? If an object such as a piece of wood floats on water it is less dense than water vs. if a rock sinks, it is more dense than water. Density examples: ***See top menu bar for more examples*** Oil and vinegar salad dressing: The oil floats on the vinegar water mixture, while the solids sink to the bottom.

Oil spills: What happens when an oil tanker leaks on the ocean? The oil floats on the water since it is less dense, and this provides some opportunity to clean up the oil spills by skimming the oil from the surface of the water.

Ice: Everyone knows that ice floats on water, but did you know that this is an abnormal physical property of solid/liquid state of water? The more normal physical property is for the solid of a compound to sink in its own liquid.

Mathematical Definition of Density

The formal definition of density is mass per unit volume. Usually the density is expressed in grams per mL or cc. Mathematically a "per" statement is translated as a division. cc is a cubic centimeter and is equal to a mL Therefore,

Density = mass = g/mL
volume

Mass vs. Weight: Although the terms mass and weight are used almost interchangeably, there is a difference between them. Mass is a measure of the quantity of matter, which is constant all over the universe. Weight is proportional to mass but depends on location in the universe. Weight is the force exerted on a body by gravitational attraction (usually by the earth).

Example: The mass of a man is constant. However the man may weigh: 150 lbs on earth, 25 lbs on the moon (because the force of gravity on the moon is 1/6 that of the earth), and be "weightless" in space.

Densities of Common Elements and Compounds

Substance Density grams per mL

Pine wood 0.35 -0.50

Water 1.00

Salt, NaCl 2.16

Aluminum, Al 2.70

Iron, Fe 7.80

Gold, Au 19.30

Mercury, Hg 13.5

In order to determine the density of an object, it is necessary to know: the mass, the volume of the substance, and the definition of density.

Density = mass (g) volume (mL) Example: Calculate the density in g/mL of aluminum if a 50 mL block weighs135 g. Solution: Apply the definition: Density = 135 g = 2.70 g/mL 50 mL If the density of a substance and either mass or volume is known, volume or mass, respectively, can be calculated using either simple algebra or dimensional analysis. The density must be translated as a conversion factor.

Example: Calculate the mass in a 200 cc block of Titanium with a density of 4.51 g. per cc. Solution: The density translated as a conversion factor is:

4.51 g = 1 cc - "per" is equivalent to an equal sign.

200 cc x 4.51 g = 902 g 1 cc

What are Physical Properties and Changes?

Physical Properties:

Physical properties can be observed or measured without changing the composition of matter. Physical properties are used to observe and describe matter.

Physical properties include: appearance, texture, color, odor, melting point, boiling point, density, solubility, polarity, and many others.

The three states of matter are: solid, liquid, and gas. The melting point and boiling point are related to changes of the state of matter. All matter may exist in any of three physical states of matter.

In the graphic on the left the solid and liquid forms of water - ice are shown.

Physical Changes:

A physical change takes place without any changes in molecular composition. The same element or compound is present before and after the change. The same molecule is present through out the changes. Physical changes are related to physical properties since some measurements require that changes be made.

Melting Point: As solid matter is heated it eventually melts or changes into a liquid state at the melting point.

Ice (a solid form of water) melts at 0 oC and changes to the liquid state.

Carbon dioxide melts at -56.6oC

Boiling Point: As the liquid matter is heated further it eventually boils or vaporizes into a gas at the boiling point.

Liquid water boils and changes into a gas, usually called steam or water vapor at 100 oC. In all three states the same molecules of water (H2O) are present.

Carbon dioxide boils at -78.5oC

In the graphic on the left a block of dry ice as a solid is changing to the gaseous state. The molecules of CO2 are present throughout.

Sublimation:

Iodine has a relatively unique property in that it can change directly from a solid to a gaseous state without going through the liquid state. As the iodine is heated it undergoes a physical change to the gas state as shown in the graphic on the left. Iodine in the gas state is a beautiful violet color.

What are Chemical Properties and Changes?

Chemical Properties:

Chemical properties of matter describes its "potential" to undergo some chemical change or reaction by virtue of its composition. What elements, electrons, and bonding are present to give the potential for chemical change.

It is quite difficult to define a chemical property without using the word "change". Eventually you should be able to look at the formula of a compound and state some chemical property. At this time this is very difficult to do and you are not expected to be able to do it.

For example hydrogen has the potential to ignite and explode given the right conditions. This is a chemical property.

Metals in general have they chemical property of reacting with an acid. Zinc reacts with hydrochloric acid to produce hydrogen gas. This is a chemical property.

Chemical Changes or Reactions:

Chemical change results in one or more substances of entirely different composition from the original substances. The elements and/or compounds at the start of the reaction are rearranged into new product compounds or elements.

A chemical change alters the composition of the original matter. Different elements or compounds are present at the end of the chemical change. The atoms in compounds are rearranged to make new and different compounds.

Magnesium reacts with oxygen from the air producing an extremely bright flame. This is a chemical change since magnesium oxide has completely different properties than magnesium metal shown on the left.

The atoms are rearranged - diatomic oxygen molecules are split apart so that one oxygen atom combines with one magnesium atom.

Oxidation of Iron - a chemical change:

For example iron has the potential to rust given the right conditions. This is a chemical property.

If iron does rust, this is a slow chemical change since rust is an iron oxide with different properties than iron metal.

In the graphic on the left, iron or steel wool is burning in a fast reaction with oxygen as contrasted with the slow rusting of iron also with oxygen.

In the element iron only atoms of iron are in contact with each other. In the element oxygen each oxygen is joined with one other to make a diatomic molecule. These atoms and molecules are rearranged so that two iron atoms combine with three atoms of oxygen to form a new compound.

Alka Seltzer

The reactions in both of the (left and lower) cases start when a solid tablet is dropped into water. The chemicals in dry solid form must dissolve in the water before a reaction may take place. In both cases gas bubbles are observed. This is an initial chemical reaction. A flaming or glowing splint is used to test for the identity of the gases by using their chemical properties.

Reactions:

Alka-Seltzer: (Baking soda or sodium bicarbonate) NaHCO3 + Citric acid ---> CO2 + H2O + Sodium Citrate

QUES.: Define chemical property. Then use this definition to describe the behavior toward the flaming splint for carbon dioxide in the example on the left.

Answer: A chemical property defines whether a chemical reaction will or will not take place. Because the flame goes out, this shows that the chemical property of carbon dioxide gas is that no combustion reaction can take place in its presence.

Efferdent

The reactions in both of the (left and upper) cases start when a solid tablet is dropped into water. The chemicals in dry solid form must dissolve in the water before a reaction may take place. In both cases gas bubbles are observed. A flaming or glowing splint is used to test for the identity of the gases.

Reaction

: Efferdent: (sodium perborate - a source of hydrogen peroxide) = H2O2 + catalyst ---> O2 + H2O

QUES.: Define chemical property. Then use this definition to describe the difference in behavior toward the flaming splint for both gases in the above examples.

Zinc and Iodine Reaction

The reaction in this case is between two elements, zinc metal and iodine. Both look sort of grayish in the photo. The reaction is started between the dry powders by adding a few drops of water. The reaction occurs as a combination reaction between the two elements to produce a single compound. During the reaction zinc metal gives two electrons to two iodine atoms to produce zinc +2 ions and iodide -1 ions.

The reaction is: Zn metal + I2 ----> ZnI2

The reaction between the two elements to produce zinc iodide is very exothermic. Some of the unreacted iodine solid is heated to a gaseous iodine which is purple in color.

QUES.: A molecule is only defined as the simplest part of a compound with two or more atoms. (True or False)

QUES.: For an exothermic reaction, heat is given off in the process. (True or False)

QUES.: The fact that unreacted iodine changes to gaseous iodine is a: chemical or physical change?

What are Mixtures and Solutions?

A MIXTURE is a combination of two or more substances that are not chemically united and do not exist in fixed proportions to each other. Most natural substances are mixtures.

In the graphic on the left there are four substances - water, alcohol, oil, and food color dye.

MIXTURES

PURE COMPOUNDS

A mixture can be physically separated into pure compounds or elements. A pure compound has a constant composition with fixed ratios of elements. Just about everything that you can think of is probably a mixture. Even the purest of materials still contain other compounds as impurities. Although it is almost physically impossible to isolate absolutely pure substances, a substance is said to be pure if no impurities can be detected using the best available analytical techniques.

Mixtures may exhibit a changing set of physical properties.

For example, mixture of alcohol and water boils over a range of temperatures.

Physical properties such as boiling point or melting point of pure substances are invariant.

For example, pure water boils at 100 degrees C

HOMOGENEOUS MIXTURES

HETEROGENEOUS MIXTURES

The prefixes "homo"- indicate sameness The prefixes: "hetero"- indicate difference. A homogeneous mixture has the same uniform appearance and composition throughout. Many homogeneous mixtures are commonly referred to as solutions.

A heterogeneous mixture consists of visibly different substances or phases. The three phases or states of matter are gas, liquid, and solid.

Particle size distinguishes homogeneous solutions from other heterogeneous mixtures. Solutions have particles which are the size of atoms or molecules - too small to be seen.

A colloid is a homogeneous solution with intermediate particle size between a solution and a suspension. Colloid particles may be seen in a beam of light such as dust in air in a "shaft" of sunlight. Milk, fog, and jello are examples of colloids. In contrast a suspension is a heterogeneous mixture of larger particles. These particles are visible and will settle out on standing. Examples of suspensions are: fine sand or silt in water or tomato juice.

Corn oil is homogeneous, White vinegar is homogeneous. A sugar solution is homogeneous since only a colorless liquid is observed. Air with no clouds is homogeneous. For example beach sand is heterogeneous since you can see different colored particles. Vinegar and oil salad dressing is heterogeneous since two liquid layers are present, as well as solids. Air with clouds is heterogeneous, as the clouds contain tiny droplets of liquid water.

SOLUTIONS are homogeneous mixtures.

A solution is a mixture of two or more substances in a single phase. At least two substances must be mixed in order to have a solution. The substance in the smallest amount and the one that dissolves or disperses is called the SOLUTE. The substance in the larger amount is called the SOLVENT. In most common instances water is the solvent. The gases, liquids, or solids dissolved in water are the solutes.

In the graphic, the blue bottle is a homogeneous solution mixture of water, KOH, glucose, oxygen gas dissolved, and methylene blue - an indicator. Since solutions are mixtures, their compositions may vary over a very wide range. The concentrations may be expressed using a variety of measures. The non-specific terms concentrated and dilute are sometimes used. A concentrated solution has a relatively large (but non-specific) amount of solute dissolved in a solvent. A dilute solution has a smaller quantity of solute dissolved.

TYPES OF SOLUTIONS

Concentrations

Solute Less than 50%

Solvent More than 50%

Examples
liquid
liquid
alcohol - water wine beer, vodka acetic acid / water - vinegar
solid
liquid
salt - water
saline (NaCl) solution
sugar solution
CaCO3 - hard water
gas
liquid
oxygen - water
CO2 - carbonated water
NH3 - ammonia solution
gas gas air = oxygen - nitrogen gas solid hydrogen - platinum liquid gas water in air solid gas smog liquid solid mercury - another metal solid solid alloy
What is an Atom?

COMPOSITION OF MATTER

MATTER is is anything which has weight and occupies space. Matter is all things that we can see, feel, and smell in our daily living. Chemistry is the study of matter. Matter is the "stuff" all around us.

In order to understand the properties and reactions of matter, it must be divided into simpler, less complex substances. It is easier to work with the definitions if we start with the smallest pieces of matter and gradually work up to more complex matter. The development of the Atomic Theory takes this approach.

ATOM THEORY OF MATTER - History

The earliest ideas about matter and atoms were developed by Greek philosophers between 450 and 380 B.C. At that time, the question under discussion was whether matter had the property of being continuous or discontinuous. These concepts can be visualized if you took the "lead" or graphite of a broken pencil point and divided it in half, then divided that piece in half and again half of that piece. This process could be continued as long as possible. If matter was continuous, the process could be continued indefinitely without ever "running out" of graphite. If matter was discontinuous, then at some point, the dividing process would end when the last particle which could still be called graphite was all that remained. A further division would result in destroying the matter called graphite.

ATOMS
Democritus used the word "atomos" meaning "indivisible" or "uncuttable" to describe the ultimate building blocks of matter. ATOMS result from the repeated division of matter to very very tiny, permanent, indivisible, invisible bits of matter with definite size and shape. This Atom Theory was applied in support of the Discontinuous Theory of Matter. Since there was no means to test such a hypothesis, other philosophers such as Plato and Aristotle argued for the Continuous Theory of Matter. The Continuous Theory of Matter received wide spread support until the 1800's when John Dalton revived the atom concept to explain certain aspects of chemical reactions.

The final division of matter such as graphite results in atoms of the element carbon.

What is Specific Gravity?

Specific gravity is a special case of relative density. In this case the density of a substance is divided by the density of water at 4 F (0 C). Since water has a density of 1 gram/cm3, and since all of the units cancel, specific gravity is the same number as density but without any units (adimensional).

Relative density is another adimensional number which measures density of any substance in relation to another. A relative density greater than one means that the substance in the numerator has a bigger density than the one in the denominator and vice versa.

Applying the same concept to specific gravity: if the substance is not miscible with water (do not mix or dissolve) it will float for specific density over one and will sink for specific gravity under one.

Density is the ratio between mass and volume. It reveals interesting features of a substance and is essentially related with the way the atoms and molecules in the substance are arranged. It will depend on the temperature among other things. Specific Gravity Determination

Liquids: The specific gravity of a liquid can be determined with a hydrometer. The depth to which the hydrometer sinks is inversely proportional to the specific gravity of the liquid. A hydrometer is a hollow, sealed, calibrated glass tube.

Solids: Some electronic scales can measure specific gravity of solids. This is particularly useful for purity determination in gems.

Gases: The specific gravity of gases is measured by specific gravity transducers. They are particularly useful for power, oil, gas, aerospace and process industries.

What does a refractometer do?

Practical uses of Specific Gravity

Specific gravity measurements can be used in a wide variety of industries. It is particularly useful because it allows access to molecular information in a non invasive way.

Purity in gems: comparing the specific gravity of a gem with the patron number (measured over a gem with high purity level), the degree of purity of a gem can be observed. This allows for fast determinations of the value of a gem.

Eggshell thickness: The eggshell thickness is an important factor in the poultry industry; it will decay with the age of the hen or under adverse conditions. If the thickness goes under certain expected values, the eggs are not marketable. The specific gravity of an egg is determined mainly by its shell, the other components have specific gravity close to one (shell= 2.325; yolk= 1.032; albumen= 1.038; shell membranes= 1.075). Measuring the specific gravity of the egg as a whole one has a good idea of the state of the shell.

Compressive strength of soils: Engineers need to know the compressive strength of a soil to choose among other things the construction method. Specific gravity and compressibility are highly connected and can be obtained one from the other.

Oil Industry: Crude oil and its refined products are normally measured either by volume in gallons and US barrels, or by weight in tons. The relationship between volume and weight can be measured by specific gravity or density. The specific gravity is related with the "degree API", a measure of the inherent power of the oil (regular, super, etc).

Table of Specific Gravities used in the Oil Industry
Product Specific Gravity Ranges
Crude oils 0.80-0.97
Aviation gasolines 0.70-0.78
Motor gasolines 0.71-0.79
Kerosines 0.78-0.84
Gas oils 0.82-0.90
Diesel oils 0.82-0.92
Lubricating oils 0.85-0.95
Fuel oils 0.92-0.99
Asphaltic bitumens 1.00-1.10
What Is a Chemical?

Answer: Short answer: Everything is a chemical. Longer answer: Chemistry is the study of matter and its interactions with other matter. Anything made of matter is therefore a chemical. Any liquid, solid, gas. Any pure substance; any mixture. Water is a chemical. Technically speaking, so is a chunk of your computer. A chemical can often be broken down into components, as is true with your computer. However, people generally use the term 'chemical' to refer to a substance that appears homogeneous or the same throughout its structure.

What Is a Chemical Element?

Elements may be thought of as the basic chemical building blocks of matter. Depending on how much evidence you require to prove a new element has been created, there are 117 or 118 known
Category:Chemical substances
Category:Materials
Aluminum
Iron
Chemistry