Useful Chemistry Resources

 

 

Periodic table

 

1.0 H 1

4.0 He 2

6.9 Li 3

9.0 Be 4

10.8 B 5

12.0 C 6

14.0 N 7

16.0 O 8

19.0 F 9

20.2 Ne 10

23.0 Na 11

24.3 Mg 12

27.0 Al 13

28.1 Si 14

31.0 P 15

32.1 S 16

35.5 Cl 17

39.9 Ar 18

39.1 K 19

40.1 Ca 20

45.0 Sc 21

47.9 Ti 22

50.9 V 23

52.0 Cr 24

54.9 Mn 25

55.8 Fe 26

58.9 Co 27

58.7 Ni 28

63.5 Cu 29

65.4 Zn 30

69.7 Ga 31

72.6 Ge 32

74.9 As 33

79.0 Se 34

79.9 Br 35

83.8 Kr 36

85.5 Rb 37

87.6 Sr 38

88.9 Y 39

91.2 Zr 40

92.9 Nb 41

95.9 Mo 42

- Tc 43

101 Ru 44

103 Rh 45

106 Pd 46

10 Ag 47

112 Cd 48

115 In 49

119 Sn 50

122 Sb 51

128 Te 52

12 I 53

131 Xe 54

133 Cs 55

137 Ba 56

139 La 57

178 Hf 72

181 Ta 73

184 W 74

186 Re 75

190 Os 76

192 Ir 77

195 Pt 78

197 Au 79

201 Hg 80

204 Tl 81

207 Pb 82

209 Bi 83

- Po 84

- St 85

- Rn 86

- Fr 87

- Ra 88

- Ac 89

- Rf 104

- Db 105

- Sg 106

- Bh 107

- Hs 108

- Mt 109

- Unn 110

- Uuu 111

- Uub 112

- Uuq 114

- Uuh 116

- Uuo 118

Lanthanides

140 Ce 58

141 Pr 59

144 Nd 60

- Pm 61

150 Sm 62

152 Eu 63

157 Gd 64

159 Tb 65

163 Dy 66

165 Ho 67

167 Er 68

169 Tm 69

173 Yb 70

175 Lu 71

Actinides

- Th 90

- Pa 91

- U 92

- Np 93

- Pu 94

- Am 95

- Cm 96

- Bk 97

- Cf 98

- Es 99

- Fm 100

- Md 101

- No 102

- Lw 103

 

 

 

S Block – Group 1, 2

When bonding these elements lose electrons to reach the stability of the nearest noble gas structure and therefore form positive ions also known as cations e.g Sodium ₁₁Na (2,8,1) loses its outer electron to become Na⁺ (2,8).

 

P Block – Group 3

When bonding these elements also lose electrons to become positive ions e.g. Al becomes Al³⁺

 

P Block – Group 5, 6, 7

When bonding these elements gain electrons to form the nearest noble gas structure and therefore become negative ions or anions e.g. Chlorine ₁₇Cl (2,8,7) gains an outer electron to become Cl^-(2,8,8).

 

D Block – Transition metals

In general these form metallic bonds.

 

 

 

Common Ions and molecules you must know:

 

                                                Examples:

Group 1 – Positive ions              Li⁺        Na⁺

Group 2 – 2 Positive ions           Be²⁺     Mg²⁺

Group 3 – 3 Positive ions           Al³⁺     

Group 6 – 2 Negative ions          O^2-       S^2-

Group 7 – Negative ions            F^-         Cl^-

 

 

 

 

Ions that cannot be predicted easily from their position in the periodic table

These are ions of common elements that you must learn.

 

Silver                                        Ag⁺

Copper                                     Cu²⁺

Iron (II)                                                Fe²⁺

Iron (III)                                   Fe³⁺

Hydrogen                                  H⁺

Ammonium                               NH₄⁺

Lead                                         Pb²⁺

Zinc                                          Zn²⁺

 

Carbonate                                 CO₃^2-

Hydroxide                                 OH^-

Nitrate                                      NO₃^-

Sulphate                                    SO₄^2-

Hydrogencarbonate                   HCO₃^-

Hydrogensulphate                      HSO₄^-

 

 

 

Common molecules that you must know:

 

Ethanol                                     C₂H₅OH

Hydrogen Peroxide                    H₂O₂

Hydrogen Sulphide                    H₂S

Nitric Acid                                HNO₃

Sulphuric Acid                           H₂SO₄

Hydrochloric Acid                     HCl

 

 

 

Basic Chemical equations:

 

Metal + Acid -> Salt + Hydrogen

Mg _(s) + 2HCl _(ag) -> MgCl_{2 (aq)} + H_{2 (g)}

 

Metal Carbonate + Acid -> Salt + Carbon Dioxide + Water

Na₂CO_{3 (aq)} + H₂SO_{4 (aq)} -> Na₂SO_{4 (aq)} + CO_{2 (g)} + H₂O _(l)

 

Acid + Alkali -> Salt + Water

HCl _(aq) + NaOH _(aq) -> NaCl _(aq) + H₂O _(l) 

 

Element + Element -> Compound

2Na _(s) + Cl_{2 (g)} -> 2NaCl _(s)

 

 

 

A balanced equation – Stochiometry (Element measure)

Example:          

H₂ + O₂ -> H₂O

2 oxygen atoms on the left hand side : only 1 on the right

 

H₂ + O₂ -> 2H₂O

2 hydrogen atoms on the left : 4 on the right

 

Balanced:                      2H₂ + O₂ -> 2H₂O

4 hydrogen atoms and 2 oxygen atoms: 4 hydrogen atoms and 2 oxygen atoms

 

 

 

Room Temperature    25 °C    ->        298 K

                                    0 °C      ->        273 K

Room Pressure           100 kPa or 1 atm

 

 

 

Common definitions

 

Atom

Smallest unit of matter, which cannot be broken down into anything simpler chemically.

 

Molecule

A group of atoms joined together by covalent bonds.

 

Atomic Number

The number of protons in an element, which is equal to the number of electrons in a neutral atom.

 

Mass Number

The total number of protons and neutrons in an atom.

 

Ion

A charged atom that has lost or gained electrons giving it a positive or negative charge.

 

Element

A substance that contains only one type of atom.

 

Compound

A substance formed by the chemical combination of elements.

 

Chemical symbol

Letters used to represent an element.

 

Molecular formula

Shows the total number of atoms of each element present in a molecule.

 

Anion

Negative ion, moves to the anode.

 

Cation

Positive ion, moves to the cathode.

 

Salt

An ionic compound.

 

Precipitate

An insoluble solid formed when two solutions mix.

 

 

 

Common Equations

 

Solubility rules

When dealing with a precipitate reaction (a reaction between two solutions which forms an aqueous solution and a solid compound) you will often be required to write state symbols. Therefore, you should know basic solubility rules so you are aware which compounds are aqueous in water.

 

Compounds	Solubility in water
Group 1 Compounds	All soluble
Ammonium Compounds	All soluble
Nitrates	All soluble
Group 7 compounds (Halides)	All soluble except silver and lead halides
Sulphates	All soluble except lead and barium sulphate
Carbonates	All insoluble except group 1 and ammonium
Hydroxides	All insoluble except group 1 and ammonium
Oxides	All insoluble (Caution! Group 1 oxides react with water)