Bonding and structure

Question 1

Describe the three types of chemical bonding

1. ionic bonding

Answer 1

Occurs between metals and non-metals. Electrons are transferred from metal atoms to non-metal atoms, forming positive and negative ions that are held together by electrostatic forces.

Question 2

2. covalent bonding

Answer 2

Occurs between non-metals. Atoms share pairs of electrons to achieve full outer shells.

Question 3

3. metallic bonding

Answer 3

Occurs in metals. Positive metal ions are surrounded by a sea of delocalized electrons, creating strong bonds.

Question 4

Explain why ionic compounds have high melting points.

Answer 4

Ionic compounds have strong electrostatic forces of attraction between oppositely charged ions. These forces require a large amount of energy to overcome, resulting in high melting points.

Question 5

Explain why graphite conducts electricity but diamond does not.

Answer 5

In graphite, each carbon atom is bonded to three other carbon atoms, leaving one electron delocalized. These delocalized electrons can move and carry a charge. In diamond, all four outer electrons are involved in covalent bonds, so there are no free electrons to conduct electricity.

Question 6

Describe the bonding and structure in diamond.

Answer 6

Diamond is a giant covalent structure where each carbon atom is covalently bonded to four other carbon atoms in a tetrahedral arrangement. This structure gives diamond its hardness and high melting point.

Question 7

Explain why graphite is used as a lubricant.

Answer 7

In graphite, the layers of carbon atoms are held together by weak forces of attraction, allowing them to slide over one another easily. This makes graphite a good lubricant.

Question 8

Why are alloys harder than pure metals?

Answer 8

Alloys contain atoms of different sizes, which distort the regular arrangement of atoms in a metal. This makes it harder for the layers of atoms to slide over each other, increasing hardness.