Group 1 and 7 Elements

Question 1

For Group 1, how do the melting and boiling points change going down the group?

Answer 1

They both decrease.

Question 2

Do Group 1 elements have a low or high density, and what does this mean for flotation?

Answer 2

They have a low density so lithium, sodium and potassium float on water.

Question 3

What do all Group 1 elements react with?

Answer 3

-Oxygen - a layer of oxide forms.

• Water - hydrogen gas and a metal hydroxide.
  - Metal hydroxides are soluble in water with high pH.

-Halogens (group 7) - salts are formed that are white or colourless crystals.

Question 4

What can compound alkali metals do in water?

Answer 4

Dissolve.

Question 5

For Group 1, how does reactivity change going down the group?

Answer 5

The reactivity increases.

Question 6

What do all Group 7 elements exist as?

Answer 6

Small molecules made up of pairs of atoms - diatomic.

Question 7

What are Group 7 elements known as?

Answer 7

Halogens.

Question 8

What are Group 1 elements known as?

Answer 8

Alkali metals.

Question 9

For Group 7, how do the melting and boiling points change going down the group?

Answer 9

They both increase.

Question 10

What colour is fluorine and what is its state of matter at room temperature?

Answer 10

Pale yellow - gas.

Question 11

What colour is chlorine and what is its state of matter at room temperature?

Answer 11

Green - gas.

Question 12

What colour is bromine and what is its state of matter at room temperature?

Answer 12

Red-brown - liquid.

Question 13

What colour is iodine and what is its state of matter at room temperature?

Answer 13

Grey - solid.

Question 14

What are all Group 7 elements poor conductors of?

Answer 14

Thermal energy and electricity.

Question 15

How many electrons do all halogens have on the outer shell?

Answer 15

Seven electrons.

Question 16

What do all halogens form?

Answer 16

Ionic compounds with metal in which the halide ions have a charge of 1-.

Question 17

What do halogens bond covalently with and what do they form?

Answer 17

Non-metals, forming molecules.

Question 18

For Group 1, how does reactivity change going down the group?

Answer 18

The reactivity decreases.

Question 19

Explain displacement with halogens.

Answer 19

A more reactive halogen can displace a less reactive halogen from an aqueous solution.

Question 20

Why does the reactivity increase going down Group 1?

Answer 20

Because outer the outer electron is less strongly attracted to the nucleus so can more easily be given, due to:

• More distance between the nucleus.
• More shells with more electrons repelling it.

Question 21

Why does the reactivity increase going down Group 7?

Answer 21

Because the attraction of the outer electrons to the nucleus decreases, reducing the attraction of the nucleus for an incoming electron, due to:

• More distance between the nucleus.
• More shells with more electrons repelling it.