bonds + forces

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.
• between metals and non metals

Question 2

How are ionic compounds

held together?

Answer 2

● They are held together in a giant ionic 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 req a lot of energy to break)
● Do not conduct electricity when solid
● Conduct when molten or dissolved in water - ions are free to move, and carry an electrical charge.

Question 4

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

Answer 4

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 2, so has 2 available outer shell electrons.
- O is in Group 6, so can accept 2 electrons to get a full outer shell configuration.
»> Mg becomes Mg2+ and O becomes O2− (oxide).

Question 5

What is a covalent bond?

Answer 5

Covalent bond is a shared pair of electrons between two atoms, between non metals

Question 6

Describe the structure and
properties of simple molecular
covalent substances

Answer 6

• Do not conduct electricity (no ions)
• Small molecules
• Weak intermolecular forces between the molecules, easy to overcome, therefore:
• Low melting and boiling points, usually gases or liquids

Question 7

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

Answer 7

They increase. That causes melting/boiling points to increase as well