4.1 Types Of Bonding and 4.2 Ionic Bonding And Structure

Question 1

What is a cation?

Answer 1

A cation is a positive ion and is formed when atoms usually of metallic elements lose electrons.

Question 2

What is an anion?

Answer 2

An anion is a negative ion and is formed when atoms usually of non metallic elements gain electrons.

Question 3

What happens to electrons when an ionic compound is formed?

Answer 3

When an ionic compound is formed electrons are transferred from one atom (metal) to another atom (non metal) to form positive and negative ions.

Question 4

What is the formula for an ammonium ion?

Answer 4

NH4+

Question 5

What is the formula for a hydroxide ion?

Answer 5

OH-

Question 6

What is the formula for a nitrate ion?

Answer 6

NO3-

Question 7

What is the formula for a hydrogen carbonate ion?

Answer 7

HCO3-

Question 8

What is the formula for a carbonate ion?

Answer 8

CO32-

Question 9

What is the formula for a sulphate ion?

Answer 9

SO42-

Question 10

What is the formula for a phosphate ion?

Answer 10

PO43-

Question 11

How do you work out the overall charge on an ionic compound?

Answer 11

The charge on an ionic compound is always zero, so the charges cancel out.

Question 12

What is ionic bonding?

Answer 12

The electrostatic attraction between oppositely charged ions.

Question 13

What does electrostatic attraction mean?

Answer 13

Electrostatic attraction means positive charges attract negatives charges and vice versa.

Question 14

What is the structure of ionic substances?

Answer 14

A crystal of an ionic salt consists of a giant lattice made up of the positive and negative ions eg Cl- and Na+. There are strong electrostatic forces of attraction between the oppositely charged ions.

Question 15

Why do ionic substances have high melting points?

Answer 15

Because a lot of energy must be supplied to overcome the strong electrostatic forces.

Question 16

Why does an ionic substance like Magnesium Oxide have a higher melting point than Sodium Chloride?

Answer 16

Because magnesium oxide has 2+ and 2- ions in the lattice which are stronger than the 1+ and 1- ions in the Sodium Chloride lattice. The ions are also smaller in MgO which also leads to stronger electrostatic attractions.

Question 17

When will ionic compounds conduct electricity?

Answer 17

Ionic compounds do not conduct electricity in the solid state since the ions are not free to move but do conduct when molten or in aqueous solution since the ions are free to move around.