C2 Bonding (Part 1)

Question 1

What is ionic bonding?

Answer 1

Ionic bonding is the electrostatic attraction between positive and negative
ions.
It is a relatively strong attraction.

Question 2

How are ionic compounds

held together?

Answer 2

● They are held together in a giant lattice.
● It’s a regular structure that extends in all directions in a
substance.
● Electrostatic attraction between positive and negative ions holds
the structure together.

Question 3

State properties of ionic

substances

Answer 3

● High melting and boiling point (strong electrostatic forces between
oppositely charged ions)
● Do not conduct electricity when solid (ions in fixed positions).
● Conduct when molten or dissolved in water - ions are free to move.

Question 4

Give 5 examples of positive ions

Answer 4

Positive: 
Na+
Mg2+
Al3+
Ca2+
Rb+

Question 5

Give 5 examples of negative ions

Answer 5

Negative: 
Cl−
Br−
SO4 2− (sulfate)
NO3− (nitrate)
OH− (hydroxide)

Question 6

What is important when working out a formula of

an ionic compound?

Answer 6

Ionic compounds are electrically neutral, i.e. positive and negative charges
balance each other.

Question 7

How are ionic compounds
formed?
Explain in terms of
MgO case.

Answer 7

Reaction of a metal with a non-metal.

Electron transfer occurs:
- metal gives away its outer shell
electrons to non-metal.

Mg is in Group II, so has 2 available outer shell electrons.

O is in Group VI, so can accept 2 electrons to get a full outer shell
configuration.

Mg becomes Mg2+ and O becomes O2− (oxide).

Question 8

What is a covalent bond?

Answer 8

Covalent bond is a shared pair of electrons between two atoms.

Question 9

Describe the structure and
properties of simple molecular
covalent substances

Answer 9

• Do not conduct electricity (no ions)
• Small molecules
• Weak intermolecular forces, therefore:
• Low melting and boiling points

Question 10

How do intermolecular forces
change as the mass/size of the
molecule increases?

Answer 10

They increase. That causes melting/boiling points to increase as well (more energy needed to overcome these forces).

Question 11

What are polymers?

Answer 11

Polymers are very large molecules (>100s, 1000s of atoms) with atoms linked by
covalent bond

Question 12

What are thermosoftening polymers?

Answer 12

Thermosoftening polymers - special type of polymers

They melt/soften when
heated.
There are no bonds between polymer chains.
Strong intermolecular forces ensure that the structure is solid at room temperature.
These forces are overcome with heating - polymer melts.

Question 13

What are giant covalent

substances? Give examples

Answer 13

• Solids, atoms covalently bonded together in a giant lattice.
• High melting/boiling points – strong covalent bonds.
• Mostly don’t conduct electricity (no delocalised e−)
• Diamond, graphite, silicon dioxide.