Topic 4.1: Ionic bonding and structure

Question 1

Definition of cations

Answer 1

Atoms that lose electrons to form a noble gas e- configuration and have a positive net charge

Question 2

Definition of anions

Answer 2

Atoms that gain electrons to form a noble gas e- configuration and have a negative net charge

Question 3

Ionic bonding

Answer 3

Sum of all the electrostatic attractive and repulsive forces between all the ions in a lattice

Question 4

What is the tendency of most elements at losing or gaining electrons regarding electron configuration?

Answer 4

Since noble gas e- configuration is the most stable, most elements will try to reach it by either losing or gaining electrons

Question 5

What elements are involved in the formation of an ionic compound?

Answer 5

Reaction between metals and non-metals

Question 6

How is an ionic compound formed?

Answer 6

a) When metals react with non-metals, electrons are transferred from the metal to non-metal forming an ion
b) Ionic bonds form as a result of the electrostatic attraction between oppositely charged ions, forming a lattice structure.

Question 7

How are the charged ions arranged in an ionic compound?

Answer 7

Giant ionic lattice

a) Each ion is surrounded by 6 ions with opposite charge
b) No individual ionic bonds
c) Opposite charged ions are packed as close as possible, while same charged ions are as far as possible.

Question 8

Explanation of volatility of ionic compounds

Answer 8

a) Low volatility
b) Ionic compounds have ionic bonds which are very strong, so a lot of energy is needed to break its bonds. At room temperature, there isn’t enough energy to break the lattice.

Question 9

Explanation of melting point of ionic compounds

Answer 9

a) High melting point
b) This is due to the strong electrostatic forces between the oppositely charged ions
c) When an ionic solid is melted, the electrostatic forces throughout the lattice must be broken and, because these are so strong, a lot of energy is required

Question 10

What is the relationship between the charges of the ions of a compound and its electrostatic force?

Answer 10

The force between ions is proportional to the product of the charges

Question 11

Explanation of electrical conductivity of solid ionic compounds

Answer 11

When ionic compounds are solid, the ions are not free to move as there are held in fixed positions; so, they cannot conduct electricity.

Question 12

Explanation of electrical conductivity of molten ionic compounds

Answer 12

When ionic compounds melt, the ions are free to move as they are no longer held in the crystal; so, they can conduct electricity

Question 13

What particles move when an ionic substance conducts electricity at molten state?

Answer 13

Ions are moving, not electrons

Question 14

Explanation of solubility of ionic compounds

Answer 14

Ions from a lattice structure can be separated by water molecules. This is because the energy released when ions are hydrated by water molecules pays back the energy required to break apart the ionic lattice

Question 15

Are all ionic compounds soluble in polar solvents?

Answer 15

No

Question 16

Name of the following polyatomic ions:

a) NH4 +
b) CO3 2-
c) OH -
d) SO4 2-
e) HCO3 -
f) PO4 3-
g) NO3 -

Answer 16

a) Ammonium
b) Carbonate ion
c) Hydroxide ion
d) Sulfate (VI)
e) Hydrogen carbonate
f) Phosphate (V)
g) Nitrate (V)

Question 17

Formulas of the following polyatomic ions:

a) Ammonium
b) Carbonate ion
c) Hydroxide ion
d) Sulfate (VI)
e) Bicarbonate
f) Hydrogen carbonate
g) Nitrate (V)

Answer 17

a) NH4 +
b) CO3 2-
c) OH -
d) SO4 2-
e) HCO 3 -
f) PO4 3-
g) NO3 -