Bonding, Structure And Properies Of Matter

Question 1

What type of ion do elements from group 1 form?

Answer 1

1+ ions.

Question 2

What type of ion do elements from group 7 form?

Answer 2

-1 charges.

Question 3

Describe how an ionic bond forms.

Answer 3

An ionic bond is formed by the complete transfer of some electrons from one atom to another.

Question 4

Describe the structure of a crystal of sodium chloride.

Answer 4

A face-centered cubic array of anions with an interpenetrating fcc cation lattice

Question 5

List the main properties of ionic compounds.

Answer 5

They are crystalline solids, and are brittle in nature.
They have high melting and boiling points.
They are soluble in water.
They conduct electricity in their solution and molten states.

Question 6

Describe how covalent bonds form.

Answer 6

1) When non-metal atoms bond together, they share pairs of electrons to make covalent bonds.
2) The positively charged nuclei of the bonded atoms are attracted to the shared pair of electrons by electrostatic forces, making covalent bonds very strong.
3) Atoms only share electrons in their outer shell.
4) Each single covalent bond provides one extra shared electron for each atom.
5) Each atom involved generally makes enough covalent bonds to fill up its outer shell. Having a full outer shell gives them the electronic structure of a noble gas which is very stable.
6) Covalent bonding happens in compounds of non-metals and in non-metal elements.

Question 7

Dot and cross diagram for the bonding of hydrogen.

Answer 7

Question 8

Dot and cross diagram for the bonding of water.

Answer 8

Question 9

Dot and cross diagram for the bonding of hydrogen chloride.

Answer 9

Question 10

Explain why simple molecular compounds typically have low melting and boiling points.

Answer 10

Weak intermolecular bonds.

Question 11

Describe the structure of a polymer.

Answer 11

Small units linked together to form a long molecule
Joined by strong covalent bonds
Lower boiling points than ionic or giant molecular compounds.

Question 12

Give three examples of giant covalent structures.

Answer 12

Diamond
Graphite
Silicon dioxide

Question 13

Explain why graphite can conduct electricity.

Answer 13

It has one delocalised electron.

Question 14

Explain how fullerenes could be used to deliver drugs into the body.

Answer 14

Fullerenes can be used to cage other molecules. The fullerene structure forms around another atom or molecule, which is then trapped inside. This could be used to deliver a drug into the body.

Question 15

What is metallic bonding?

Answer 15

1) Metals also consist of a giant structure.
2) The electrons in the outer shell of the metal atoms are delocalised. There are strong forces between the positive metal ions and the shared negative electrons.
3) These forces of attraction hold the atoms together in a regular structure and are known as metallic bonding. Metallic bonding is very strong
4) Substances that are held together by metallic bonding include metallic elements and alloys.
5) It’s the delocalised electrons in the metallic bonds which produce all the properties of metals.

Question 16

Explain why alloys are harder than metals.

Answer 16

When another element is mixed with a pure metal, the new metal will distort the layers of metal atoms, making it more difficult for them to slide over.

Question 17

List three properties and explain how metallic structure causes each property.

Answer 17

-Most metals are malleable: The layers of atoms in a metal can slide over each other.
-Metals are good conductors of electricity and heat: The delocalised electrons carry electrical current and thermal heat through the structure.
-Most metals are solid at room temperature: Forces between the metal atoms and the delocalised electrons are very strong meaning a lot of energy is required to to break these bonds.

Question 18

Name the three states of matter.

Answer 18

Solid
Liquid
Gas

Question 19

What is the state symbol of an aqueous substance?

Answer 19

aq

Question 20

What is the name of the temperature at which a liquid becomes gas?

Answer 20

Boiling point