Group 7 - physical properties

Question 1

What do the molecules exist as?

Answer 1

diatomic molecules

Question 2

Why does fluorine have weak bonding?

Answer 2

the small size of the fluorine atom leads to repulsion between non-bonding electrons because they are so close together

Question 3

What is the trend in the size of the atoms?

Answer 3

the atoms get bigger going down the group because each element has one extra filled main level of electrons compared with the one above

Question 4

What is the trend in electronegativity?

Answer 4

decreases down the group

due to distance between nucleus and bonding electrons, plus the shielding effect of inner shells of electrons

Question 5

What is the trend in melting and boiling points going down the group?

Answer 5

increase going down the group

this is because larger atoms have more electrons and this makes the van der Waals forces between molecules stronger point

the lower the boiling point, the more volatile the element

Question 6

What colour are the elements going down the group?

Answer 6

at room temp:

fluorine is a pale yellow gas

chlorine is a greenish gas

bromine is a red/brown liquid

and iodine is a black solid

they get denser and darker going down the group

Question 7

What are the properties of solid halogens?

Answer 7

brittle