Groups 1 and 7

Question 1

What are group 1 elements called?

Answer 1

They are called alkali metals

Question 2

What are group 7 elements called?

Answer 2

They are called halogens.

Question 3

What are two physical properties of the alkali metals?

Answer 3

. Are soft (they can be cut with a knife)
. Have relatively low melting points
. They have low densities (the first 3 in group 1 can float on water)

Question 4

Going down group 1, does the melting point increase or decrease?

Answer 4

Decreases

Question 5

What is pH?

Answer 5

Scale of acidity or alkalinity. A pH (power of hydrogen) value below 7 is acidic (1 being most acidic),7 being neutral, and a pH value above 7 is alkaline (higher meaning more alkaline (14))

Question 6

The alkali metals react with water to produce….

Answer 6

…a metal hydroxide and hydrogen.

Question 7

Does the reactivity increase or decrease going down group 1?

Answer 7

It increases as it is easier to lose 1 electron than gain 7.

Question 8

Why is sodium more reactive than lithium?

Answer 8

Sodium loses an outer electron more easily than lithium because its outer electron is further from the nucleus.

Question 9

What happens to the universal indicator when it is added to the solution produced when an alkali reacts with water?

Answer 9

It would turn purple.

Question 10

Does the melting and boiling point increase or decrease going down group 7?

Answer 10

The melting points and boiling points of the halogens increase going down group 7.

Question 11

Why does the melting and boiling point increase for the halogens?

Answer 11

It increases because :
. the molecules become larger
. the intermolecular forces become stronger
. more energy is needed to overcome these forces

Question 12

Where are alkali metals stored?

Answer 12

They are stored in oil to keep water and air away from them.

Question 13

Why does the reactivity increase as you go down the group 1?

Answer 13

. the atoms get larger
. the outer electron gets further from the nucleus
. the attraction between the nucleus and outer electron gets weaker – so the electron is more easily lost

Question 14

Does reactivity increase or decrease as you go down group 7?

Answer 14

It decreases

Question 15

Why does reactivity decrease as you go down group 7?

Answer 15

As you go down group 7, the reactivity of the halogens decreases because the atomic mass of the halogens increases. They increase in electron shells; so the atoms are larger as you go down the group. Therefore, the attraction of the outer electron to the nucleus decreases as you go down group 7.

Question 16

Why do the melting and boiling points of group 1 metals decrease as you go down?

Answer 16

It decreases because there is a decrease in the forces of attraction between the atoms.

Question 17

What is shielding?

Answer 17

When you have more shells and the forces get weaker between the nucleus and the outer most electron.

Question 18

What is reduction?

Answer 18

The loss of oxygen, gain of electrons, or gain of hydrogen by a substance during a chemical reaction.

Question 19

What is oxidation?

Answer 19

The gain of oxygen, or loss of electrons, by a substance during a chemical reaction.

Question 20

What is a redox reaction?

Answer 20

When reduction and oxidation take place at the same time.

Question 21

What are two extraction methods for metals?

Answer 21

Electrolysis and Reduction with Carbon

Question 22

What is Electrolysis?

Answer 22

The decomposition (breakdown) of a compound using an electric current. In principle, any metal could be extracted from its compounds using electrolysis. However, large amounts of
electrical energy is needed to do this, so electrolysis is expensive.

Question 23

What is reduction with carbon?

Answer 23

If a metal is less reactive than carbon, it can be extracted from its compounds by heating it with carbon as carbon would displace it. It can only be used for elements less reactive than it.

Question 24

What are 2 advantages of recycling used metals rather than mining and extracting the raw material:

Answer 24

1. It is much better for the environment as mining would release greenhouse gases which contribute to global warming.
2. It conserves the natural resources of the metal.

Question 25

State the reactivity series from most to least reactive:

Answer 25

Please: Potassium
Stop: Sodium
Calling: Calcium
Me: Magnesium
A: Aluminium
Careless: Carbon
Zebra: Zinc
Instead: Iron
Try: Tin
Learning: Lead
How: Hydrogen
Copper: Copper
Saves: Silver
Gold: Gold