2.4 - 2.7. Bonding

Question 1

Positive ions & negative ions are

Answer 1

cations, anions respectively

Question 2

An ionic bond is

Answer 2

a strong electrostatic force of attraction between two oppositely charged ions

Question 3

Ionic bonds are formed

Answer 3

when a metal donates electrons to a non-metal, forming two oppositely charged ions - this is so that both atoms can gain full outer shells.
The oppositely charged ions are now attracted to each other, and the electrostatic force of attraction between them is called an ionic bond.

• metal donates electrons to non-metal
• forms two oppositely-charged ions
• both atoms gain full outer shell
• ions now attracted to each other, electrostatic force of attraction between ions known as an ionic bond

Question 4

Ionic compounds are held together

Answer 4

by strong electrostatic forces of attraction between oppositely charged ions.

Question 5

Giant ionic/metallic/covalent structures have high melting & boiling points

Answer 5

because they are composed from lots of strong ionic bonds, rather than weak intermolecular forces. It takes a large amount of energy to break the many strong bonds between the oppositely charged ions; therefore, giant ionic structures have high melting and boiling points.

Question 6

They have good electrical conductivity when aqueous or molten, because

Answer 6

in these states ions are free to move and so charge can flow.

Question 7

The lattice structure formed by ionic compounds

Answer 7

is a regular arrangement of alternating positive and negative ions.

Question 8

Covalent bonds are formed

Answer 8

when pairs of electrons are shared between non-metals, so that all atoms gain full outer shells.

Question 9

Simple covalent molecules are held together

Answer 9

by a mix of strong covalent bonds and weak intermolecular forces between molecules.

Question 10

Simple covalent molecules have low melting & boiling points

Answer 10

because they are bonded together with a mix of strong covalent bonds and weak intermolecular forces. When simple covalent molecules melt/boil, only the weak intermolecular forces are broken - very little energy is required to overcome the weak intermolecular forces, so they have low melting & boiling points.

Question 11

Simple covalent compounds have poor electrical conductivity

Answer 11

because their particles do not carry any charge, and free-moving charged particles are required for electrical conductivity.