C4.1.1

Question 1

What are the Group 1 elements called and why?

Answer 1

They are called the alkali metals because they react with water to form alkaline solutions.

Question 2

What metal properties do Group 1 elements also have?

Answer 2

They are shiny when freshly cut, good conductors of electricity.

Question 3

What non-metal properties do the Group 1 elements have?

Answer 3

They are in the solid state at room temperature, but are all soft enough to cut with a knife. Each metal is softer as you go down the group.

Question 4

What is the trend as you go down the group?

Answer 4

The trends as you go down the group:
- their density increases, though sodium is denser than expected
- their melting point decreases

Question 5

Why are the Group 1 metals stored in oil?

Answer 5

They react rapidly with oxygen in the air and with water.

Question 6

What do the metals create when they react with water. For eg, what would happen with sodium?

Answer 6

The alkali metals react with water to produce a metal hydroxide and hydrogen. For example,
2Na(s) + 2H2O(l) —> 2NaOH(aq) + H2(g)

Question 7

What happens to the reactivity as you go down the group?

Answer 7

The reactivity increases as you go down.
- lithium fizzes steadily and slowly disappears
- sodium melts to form a silvery ball, fizzes vigorously, and quickly disappears
- potassium immediately ignite, burns with a lilac flame, and very quickly disappears

Question 8

Why does the reactivity go up?

Answer 8

The Group 1 elements all have similar chemical properties because all their atoms have one electron in their outer shell.
- the atomic radius increases, which increases the reactivity
- the attraction between electrons and the nucleus decreases, meaning that there is more shielding
- it is easier to lose an electron from the outer shell as you go down, which is why it becomes more reactive

X —> X+ + e-