Section 14

Question 1

Group one

Answer 1

Alkali metals
Very soft
Very reactive – increases as you go down the group – outer electron is more easily lost because it’s further from the nucleus
Form ionic compounds
Low melting and boiling points
Reactions with cold water produces a hydroxide and hydrogen gas – react vigourously

Question 2

Group 7

Answer 2

Halogens
Melting and boiling points increase as you go down the groups
Exist as diatomic molecules
Reactivity decreases going down group 7 – gets harder to attract the electron to fill the outer shell when it’s further from the nucleus
Halogens can react with metals and hydrogen, some form salts

Question 3

Halogen displacement reactions

Answer 3

Displacement reactions show reactivity trends
A more reactive halogen will displace a less reactive one
Halogen displacement reactions are redox reactions – halogens gain electrons (reduction) – how light ions lose electrons (oxidation)

Question 4

Group 0

Answer 4

Noble gases
Group 0 elements are all inert(don’t react much), colourless gases
There are patterns in the properties of noble gases – boiling and melting points and density or increase as go down group
The noble gases have many everyday uses – filament lamps airships party balloons
They are non-flammable and monatomic – there gases are made of single atoms

Question 5

Tests

Answer 5

Chlorine – use damp blue litmus paper – Blue litmus goes red then white, red litmus goes white
Hydrogen– squeaky pop test
Oxygen – relights a glowing splint
Carbon dioxide – limewater goes cloudy