3 - Ionic bonding

Question 1

Define ‘ionic bonding’

Answer 1

Ionic bonding is the electrostatic force of attraction between oppositely charged ions formed by electron transfer

Question 2

Molecular ions:

Answer 2

Hydroxide = OH^-
Nitrate = NO₃^-
Ammonium = NH₄⁺
Sulfate = SO₄^2-
Carbonate = CO₃^2-

Question 3

Formulas of ionic compounds

Answer 3

1) Write the two ions: Ca²⁺ and O^2-
2) Swap the charges: Ca^2- and O²⁺
3) Drop the charges: Ca₂ and O₂
4) Simplify to lowest whole number if needed: Ca₂O₂ simplifies to CaO

Question 4

What is an ionic substance?

Answer 4

A crystalline solid where ions are held together by ionic bonds

Question 5

What is the structure of an ionic substance?

Answer 5

Ionic substances form giant ionic lattices where each ion is surrounded by oppositely charged ions

Question 6

What are the properties of ionic substances?

Answer 6

• high melting and boiling points
• soluble
• can conduct electricity when molten or in solvent
• hard and brittle

Question 7

Why do iconic substances have high melting and boiling points?

Answer 7

The electrostatic forces holding the ionic lattice together are strong and require a lot of energy to overcome

Question 8

How can ionic substances conduct electricity when molten (melted) or when in solvent?

Answer 8

• ions are separate when molten or in solvent and are no longer held in a lattice
• they are free to move and can carry a flow of charge and create an electrical current

Question 9

Why do ionic substances not conduct electricity when solid?

Answer 9

The ions in the lattice are held in place and cannot move around to carry a charge

Question 10

How are ionic substances soluble in water?

Answer 10

The positive and negative ends of water attract the oppositely charged ions in an ionic compound allowing it to be fully dissolved

Question 11

Why are ionic substances brittle?

Answer 11

When the layers of alternating charges are distorted the charges will repel therefore breaking apart the lattice into fragments