Group 1

Question 1

Why are group 1 metals called the alkali metals?

Answer 1

They react with water to form alkaline solutions and hydrogen

Question 2

3 properties of group 1 metals:

Answer 2

• they are soft
• they have low melting and boiling points
• they have low densities

Question 3

Observations of lithium’s reaction with water

Answer 3

• metal floats
• moves across surface of water quickly
• effervescence

Question 4

Observations of sodium’s reaction with water:

Answer 4

• metal floats
• moves rapidly across surface of water
• effervescent more vigorously than lithium

Question 5

Observations of potassium’s reaction with water:

Answer 5

• metal floats
• moves rapidly across surface of water
• effervesces more vigorously than sodium
• lilac flame

Question 6

What is the trend in reactivity for group 1 metals?

Answer 6

The metals in group 1 become more reactive as you go down the group.

Question 7

Explain the trend in reactivity for group 1 metals

Answer 7

• as you go down the group
• outer electron becomes further away from nucleus
• due to increase in number of shells
• this means the outer electron is more readily lost
• less strongly attracted to nucleus

Question 8

Combustion of lithium observation.

Answer 8

Lithium burns with a red flame

Question 9

Combustion of sodium observations

Answer 9

Sodium burns with an orange-yellow flame

Question 10

Combustion of potassium observations

Answer 10

Potassium burns with a lilac flame

Question 11

Which out of lithium, sodium and potassium tarnishes the most quickly and why?

Answer 11

Potassium tarnishes the most quickly as it is the most reactive.

Question 12

General equation for group 1 metals and water

Answer 12

Alkali metal + water -> metal hydroxide + hydrogen