Section 6 - Group 7 Flashcards
Group 7 elements all have 7 electrons in their outer shell. As a result, how do these elements bond?
They either:
1) Form ionic compounds by gaining an extra electron or,
2) Share a pair of electrons and form a covalent bond
In their elemental state, how do the halogens bond?
Covalently, forming diatomic molecules (two atoms joined with a single covalent bond)
What colour and state is Chlorine at room temp?
Yellow/Green gas
What colour and state is Bromine at room temp?
Brown liquid
What colour and state is Iodine at room temp?
Grey solid
As you go down group 7, does the melting and boiling points of the elements increase or decrease?
Increase
As you go down group 7, why do the melting and boiling points of the elements increase?
This is because the strength of the weak intermolecular bonds between molecules increases as the number of electrons in the molecules increases.
During their reactions, how many electrons do Group 7 elements gain from another atom?
One
Does reactivity increase or decrease as you go down Group 7?
Decrease
Why does the reactivity of the Group 7 elements decrease as you go down the group? (2)
1) As with the Group 2 elements, nuclear charge increases as you go down the group. A greater nuclear charge will attract the extra electron required to fill the outer shell more strongly. This works to increase the reactivity of the elements as you go down the group.
2) However, as the atoms get bigger, the extra shells of electrons shield the nuclear charge more effectively. So the nucleus is less able to attract the extra electron the atom wants.
- In Group 7, this shielding outweighs the effect of increasing nuclear charge. The elements at the top of the group are best able to attract an extra electron, and are more reactive.
What will happen if you mix a halogen with a solution containing halide ions?
A more reactive halogen will displace a less reactive halide ion from solution
