Group Showdown
The reactivity trends of three groups: the Group 1 alkali metals get more reactive down the group, the Group 7 halogens get less reactive, and the Group 0 noble gases are unreactive.
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The group showdown
The periodic table groups elements with similar properties. This module compares three groups: Group 1 the alkali metals, Group 7 the halogens, and Group 0 the noble gases. Each has a clear reactivity trend that you can explain using electron shells.
Words for the groups
Learn these four terms before you compare the groups.
Group 1 and Group 7
The two reactive groups trend in opposite directions.
Shells and shielding explain it
To reach the top grades, explain the trends using electron shells and shielding: down Group 1 the outer electron is further from the nucleus and more shielded, so it is lost more easily, making the metal more reactive.
Match the group to its property
- Group 1
- Group 7
- Group 0
- displacement
- the alkali metals, more reactive down the group
- the halogens, less reactive down the group
- the noble gases, which are unreactive
- a more reactive halogen takes the place of a less reactive one
Match the term to its meaning
- alkali metal
- halogen
- noble gas
- outer shell
- a soft, reactive metal in Group 1
- a reactive non-metal in Group 7
- an unreactive element in Group 0
- the outermost ring of electrons in an atom
How does Group 1 change?
How does the reactivity of the Group 1 metals change down the group?
- It increases down the group.
- It decreases down the group.
- It stays the same.
- It goes up and down from one element to the next.
True of the halogens
Select the TWO statements that are true of the Group 7 halogens.
- Reactivity decreases down the group.
- A more reactive halogen can displace a less reactive one.
- They are unreactive like the noble gases.
- Reactivity increases down the group.
Order Group 1 by reactivity
Put these Group 1 metals in order, least reactive first.
- Lithium, least reactive of these
- Sodium, more reactive
- Potassium, more reactive still
- Rubidium, the most reactive of these
Summarise the trends
In Group 1, the alkali metals get more _____ down the group. In Group 7, the halogens get less reactive down the group, and a more reactive halogen can _____ a less reactive one. Group 0, the _____ gases, are unreactive because their outer _____ is full. Reactivity trends are explained by electron shells and _____.
Count the outer electrons
A Group 1 alkali metal has how many electrons in its outer shell?
Group 1 against Group 7
Tap the TWO statements that are TRUE.
- Group 1 metals get more reactive down the group
- Group 7 non-metals get less reactive down the group
- Noble gases are very reactive
- Group 1 metals get less reactive down the group
- Halogens get more reactive down the group
Which group?
Decide which group each element belongs to.
- A soft metal that reacts with water and gets more reactive down its group
- A reactive non-metal that gets less reactive down its group
- An unreactive gas with a full outer shell
Explain the trend
Explain why the reactivity of the Group 1 metals increases down the group. Use the ideas of the outer electron, electron shells and shielding.
- Explain what happens to the outer electron down the group
- Explain the role of shielding
- Explain why this makes the metal more reactive