Group 0: unreactive gases with full outer shells
Definition
Group 0
The column on the far right of the periodic table that contains the noble gases.
- Group 0 contains the noble gases: helium, neon, argon, krypton, xenon and radon.
- Their atoms have a full outer shell of electrons (helium has 2, the others have 8).
- A full outer shell is very stable, so the atoms have no tendency to gain, lose or share electrons.
- This is why the noble gases are very unreactive (inert).
- They exist as single atoms (they are monatomic), not as molecules.
Key Idea
- A full outer shell is the reason for the noble gases' lack of reactivity.
- Other elements react in order to reach the same stable arrangement.
Boiling points increase down Group 0
Definition
Relative atomic mass
The weighted mean mass of the atoms of an element compared with one twelfth of the mass of a carbon-12 atom.
- Going down Group 0, the boiling points increase.
- Down the group, atoms have more electrons and a larger relative atomic mass.
- Larger atoms have stronger forces of attraction between them.
- More energy is needed to separate the atoms, so the boiling point is higher.
- For this reason helium (top) has the lowest boiling point and radon (bottom) the highest.
Self review
- Why are the noble gases unreactive?
- Answer: they have a full, stable outer shell, so they do not gain, lose or share electrons.
- How many outer electrons does neon have?
- Answer: 8.
- What happens to boiling point down Group 0?
- Answer: it increases.
- Why does boiling point increase down the group?
- Answer: atoms get larger with stronger forces between them, needing more energy to separate.
