Group 7

Question 1

What is fluorine (F2)?

Answer 1

Yellow, very reactive and toxic gas

Question 2

What is chlorine (Cl2)?

Answer 2

Green, very reactive and toxic gas.

When used it is diluted down.

Question 3

What is bromine (Br2)?

Answer 3

Orange/brown, very reactive and toxic liquid.

Often used as a solution in water - Bromine water (Br2 (aq)).

Question 4

What is Iodine (I2)?

Answer 4

Grey crystals (solid), that are reactive and toxic.
Easily evaporates into purple vapour on heating.
Used in solution as antiseptic (brown solution).

Question 5

Describe the atomic radius down group 7.

Answer 5

The atomic radius of the group 7 elements increases because there are more electron shells and so they are bigger atoms.

Question 6

What is electronegativity?

Answer 6

The power of an atom to attract the 2 electrons in a covalent bond.

Question 7

What happens to the electronegativity down group 7?

Answer 7

The electronegativity down group 7 decreases because they are bigger atoms so there is more shielding and so a weaker attraction between the nucleus and the two electron in the covalent bond.

Question 8

What happens to the melting and boiling groups down group 7?

Answer 8

Bigger molecules, more van der Waals’ forces so higher melting/boiling points between molecules.

Question 9

What happens to the ionisation energy energy down group 7?

Answer 9

Decreases because the atoms are bigger so there’s more shielding therefore a weaker force of attraction between the nucleus and the outer electron.