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INORGANIC CHEMISTRY
CM1000
Dr. Simon Lawrence
Definition of Inorganic Chemistry
the study of the elements in the periodic table and
their compounds except the compounds based on
carbon
Examples:
Silicon – in computer chips.
Iron – essential element in humans.
Magnesium – Milk of Magnesia.
Sodium chloride - salt.
Course outline
1.
2.
3.
4.
The Periodic Table. Types of bonding.
Structures of Main Group compounds.
Chemical reactions.
Transition elements.
Note: Page numbers refer to Brown. LeMay and
Bursten, Chemistry, The Central Science, 10th ed.
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1.1. The Periodic Table - see Fig. 2.16, p. 50
Chap. 2, p. 49-51; Chap. 6, p. 246-249; Chap. 7
261-263
 Groups with ns1 ....to ns2np5 are the main group
elements (groups 1, 2, 12 to 17)
 Group 18 with ns2np6 are the noble gases or
inert gases
 Groups with unfilled d shells i.e. ns2nd1 to 9 are
the transition elements (groups 3 to 11)
Look first at Main Group chemistry, later on at
transition elements
NB: Know the positions of the elements from H
to Kr, i.e. atomic nos. 1 to 36.
(Essential elements for life – see Fig. 2.24, p.59)
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1. 2. Formation of Chemical Compounds.
Chapter 8, p. 300-303
All chemical compounds are formed by the
interactions of electrons in the valence shells of
the elements involved.
The valence shell is the outermost shell for Main
Group elements, i.e. ns or ns np, e.g. N 2s 2p
Valence shell electrons are the electrons in the
outermost shell.
When an element is involved in chemical bonding,
it transfers or shares electrons so that its electron
configuration is the same as the nearest Noble Gas
(the Noble Gas Rule or Octet Rule) – see Prof.
Brint’s course
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1.2.1. Ionic Bonding.
Chap. 2, p.55–59; Chap. 8, p. 303-304
One of the ways to combine elements is to transfer
electrons to give ions. The compound formed is an
ionic compound. The interaction of the ions is
termed an ionic bond.
Example:
Na + Cl

[Na+][Cl-]
[3s1]
[3s23p5]
[3s0][3s23p6]
NaCl is an ionic compound containing sodium
cations and chloride anions. It is held together by
the electrostatic attraction between the ions with
opposite charges.
Any system which has a positive charge is a cation
e.g. Na+, Ca2+, [NH4]+.
Any system which has a negative charge is an
anion
e.g. Cl-, O2-, [ClO4]-.
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Metals will provide cations and non-metals will
give anions.
Cations and anions are present in living cells and in
the environment.
For example, seawater contains both Na+ and Cl- as
does blood; Na+ and K+ play an important role in
the transmission of nerve impulses.
Cations
Formed by elements on the left hand side of the
periodic table, i.e. Groups 1,2, 12 and 13. Metals.
All group 1 elements form M+ ions - ease of
formation of M+ increases as the group is
descended
All group 2 elements form M2+ ions - ease of
formation increases as the group is descended
In group 13, Al and Ga form cations i.e. [Al]3+,
[Ga]3+.
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Anions
Formed by elements on the right hand side of the
periodic table, i.e. Groups (14), 15, 16 and 17.
Non-metals.
Group 17 forms X- ions for F, Cl, Br.
Group 16 forms X2- for O, S, Se.
Group 15 forms X3- for N, P, As.
Group 14 forms X4- only for C (rare)
Summary
Ionic compounds may be formed between cations
from Groups 1,2 or 13 and anions from Groups 15,
16 or 17, e.g. Na+Cl-, Ca2+S2-, Ga3+As3-.
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Question
Give the empirical formula for the ionic compounds
formed from the following combination of
elements.
1
2
3
4
5
Na and F
Ca and S
Ga and As
K and O
Al and O