4.2 - group 7 Flashcards
1
Q
what are halogens?
A
group 7 elements
2
Q
what are the trends in properties of halogens?
A
- all are diatomic
- colours get darker down the group
- mp/bp increases down the group
3
Q
when they react with metals, halogens form _________
A
ionic compounds
4
Q
halogens get ______ reactive down the group
A
less
5
Q
why is it harder to gain an electron to fill their outer shell as you go down the group?
A
- atoms have more electron shells
- extra electron further from nucleus
- so its attraction to nucleus is weaker
6
Q
what’s the chemical test for chlorine
A
- damp blue litmus paper turns white
- this is because the chlorine acts as a bleaching agent, so it removes the colour from the paper
7
Q
what colour are the different aqueous halogens?
A
Cl₂ (aq) - colourless
br₂ (aq) - yellow
i₂ (aq) - brown
8
Q
what colour are the different aqueous salts?
A
KCl (aq) - colourless
KBr (aq) - colourless
KI (aq) - colourless
