Ionic bonding

what type of elements form ionic bonding?

• non-metallic and non-metallic

• non-metallic and metallic

• metallic and metallic

Answer explanation

By now, you should know the 'staircase' that separates metals and non-metals in the Periodic Table.

Sodium chloride is an ionic compound formed between element, sodium and chlorine. Select the statements that are true.

• Sodium atom loses electron to form Na⁺ ion.

• Sodium atom gains electron to form Na^- ion.

• Chlorine atom loses electron to form Cl⁺ ion.

• Chlorine atom gains electron to form Cl^- ion.

• Sodium and chlorine atoms share electrons to form sodium chloride.

Answer explanation

What is the chemical formula of sodium chloride?

• NaCl

• Na₂Cl

• NaCl₂

• NaCl₃

Answer explanation

Since the ratio of Na+ ion: Cl- ion is 1: 1, the chemical formula is Na₁Cl₁. However, you do not need to show "1", hence answer is NaCl.

calcium (Ca) atom has an electronic configuration of 2.8.2, whereas fluorine (F) atom has an electronic configuration of 2.7. What is the ratio of Ca:F atoms for ionic bonds to be formed between calcium and fluorine?

• 1:1

• 1:2

• 1:3

• 2:1

Answer explanation

One calcium atom loses two valence electrons to form Ca²⁺ ion, while each of the two fluorine atoms gain one valence electron to form F^- ion.

What is the chemical formula for the compound formed between calcium and fluorine?

• CaF

• Ca₂F

• CaF₂

Answer explanation

Since the ratio of Ca²⁺ ion: F^- ion is 1: 2, the chemical formula is CaF₂.

Aluminum (Al) atom has electronic configuration of 2.8.3 , while oxygen (O) atom has electronic configuration of 2.6. What is the ratio of Al:O atoms for the ionic bonds to be formed?

• 1:2

• 2:1

• 2:3

• 3:2

Explain how the ionic bonds are formed between aluminium and oxygen.

Hint: the number of atoms of each element that is required to gain / lose how many valence electrons.

What is the formula of the compound formed between aluminum and oxygen?

• AlO

• Al₂O

• Al₂O₃

• Al₃O₂

Select the physical properties of ionic compound.

Clue: classic example of ionic compounds is sodium chloride.

• They are usually soluble (can dissolve) in water.

• They are usually insoluble (cannot dissolve) in water.

• They can conduct electricity in any states.

• They can conduct electricity in molten (liquid) and aqueous (when dissolved in water) states.

• They have low melting and boiling points.

Answer explanation

Apart from the two correct properties above, ionic compounds should have high melting and boiling points and they are usually insoluble in organic solvents (such as oil).