Bonding, structure and the properties of matter - questions 1-15

What is an ion?

An atom that has become charged as it has gained or lost electrons.

Which elements form ionic bonds?

Metals and non metals.

What are the charges for ions from group 1 and 2?

Group 1 : +1 ions, group 2 : +2 ions.

What are the charges for ions from group 6 and 7?

Group 6 : -2 ions, group 7 : -1 ions.

What is the name of the force that holds oppositely charged ions together?

Electrostatic forces.

Describe the structure of a giant ionic lattice.

Billions of alternating positive and negative ions held together by electrostatic forces of attraction acting in all directions.

Why do ionic compounds have high melting points?

Electrostatic forces of attraction between the ions is strong and requires a lot of energy to break.

Why don’t ionic substances conduct electricity when a solid?

Ions are in a fixed position so cannot move, there are no delocalised electrons to carry the charge through the structure.

Why do ionic substances conduct electricity when melted or dissolved in water?

Ions are free to move and carry the charge through the structure.

How are covalent bonds formed?

By atoms sharing electrons.

Which type of atoms form covalent bonds between them?

Non metals.

Describe the structure and bonding of a giant covalent structure.

Billions of atoms bonded together by strong covalent bonds.

Describe the structure and bonding in simple covalent molecules.

Small numbers of atoms grouped together into molecules with strong covalent bonds between the atoms and weak intermolecular forces between the molecules.

Why do giant covalent substances have high melting points?

It takes a lot of energy to break the strong covalent bonds between the atoms.

Why do small covalent molecules have low melting points?

Only a small amount of energy is needed to break the weak intermolecular forces between the molecules.