Topic 1 - structure and bonding

Question 1

Bohr’s Theory…proposed a new model…

Answer 1

Electrons only exist in fixed orbitals (shells) and not anywhere in between

Each shell has a fixed energy

When an electron moves between shells electromagnetic radiation is emitted or absorbed

Because the energy of shells is fixed, the radiation will have a fixed frequency

Question 2

Refining Bohr’s Model

Answer 2

Scientists realised that not all electrons in a shell had the same energy, so the model was not quite right.

It was refined to include sub-shells

The model also explained why some elements are inert – they can only hold a fixed number of electrons and that an elements reactivity is due to its electrons.

A full shell does not react.

Question 3

Aufbau Principle

Answer 3

The order in which these sub shells fill up