Halogens
Group 7: The halogens are elements in group 7 of the periodic table.
- They have similar reactions to each other because if they gain one electron they complete their outer shell.
- They all react with metals to form compounds called halides.
- Fluorine is the most reactive halogen, and the reactivity decreases as you go down the group.
The Properties of Halogens 🤨
Fluroine's chemical symbol is 'F' and it is a gas at room temperature. The colour of Fluroine is pale-yellow.
Chlorine's chemical symbol is 'Cl' and like Fluroine it is also a gas at room temperature.
Bromine's chemical symbol is 'Br' and unlike Fluroine and Chlorine it is a liquid at room temperature.
Iodine's chemical symbol is 'I' and it is a solid at room temperature.
The Halogens are diatomic molecules, they have two atoms in them.
Halogens and Metals
In I/GCSE Chemistry, you may be asked about the reactions between the reactions between halogens and metals.
Try to write word equations and balanced equations to show the reactions between...
a) potassium and chlorine
b) calcium and bromine
potassium + chlorine → potassium chloride
2K(s) + Cl2 → 2KCI(s)
calcium + bromine → calcium bromide
Ca(s) + Br2(l) → CaBr2(s)
From above, we can see that the halogens react with metals to form compounds called halides.
Displacement Reactions 🥊
- some halogens will displace another halogen from a solution.
- the most reactive halogen is at the top of the group. This is the opposite way round to the alkali metals, where the most reactive elements are at the bottom.
References: https://sciencenotes.org/wp-content/uploads/2020/10/halogen-periodic.jpg
Drafted by Catrina (Chemistry)