10.1

Question 1

how do elements in group 7 exist?

Answer 1

they exist as diatomic molecules

Question 2

what is the appearance of halogens at room temperature? is there a trend?

Answer 2

flourine - pale yellow gas
chlorine - greenish gas
bromine - red-brown liquid
iodine - black solid

group 7 halogens get darker and denser going down the group.

Question 3

the bond energies in group 7 decrease as you go down the group. However, there is an exception. What is it?

Answer 3

Fluorine is the first element in group 7 but has a weak covalent bond. This is because of its small size. There is repulsion between two non-bonding pairs of electrons since they are close

Question 4

what is the trend of electronegativity in group 7?

Answer 4

The electronegativity of group 7 decreases as you go down the group. This is because the number of shells around the elements’ nucleus increases as you go down the group. The improved shielding around the nucleus decreases the attraction between the nucleus and the outermost electron, hence the electronegativity.

Question 5

what is the trend of the boiling and melting point down group 7?

Answer 5

As you go down group 7, the boiling and melting point increase. This is because the number of electrons increases as you go down the group. This strengthens the Van Der Waal forces between the molecules, requiring more energy to break. This makes chlorine more volatile than iodine