Atoms Flashcards
What is the term for electron ‘shells’?
Energy levels.
Does the ‘shell’ closest to the nucleus have high or low energy?
Low - the electrons use most of their energy as attraction to the nucleus.
Atoms are…?
Mostly empty space.
Describe the pair of electrons on the first energy level.
Move around in a spherical pattern - ‘s’.
The electronic configuration for this pair is 1s2.
Describe the first pair of electrons on the second energy level.
Move around in a spherical pattern - ‘s’.
The electronic configuration for this pair is 2s2.
Describe the next pairs of electrons on the second energy level.
Move around in a figure of 8 - ‘p’. Otherwise, they would overlap with the first pair of electrons. px, py & pz axes.
This sublevel has a maximum of 3 pairs of electrons. The electronic configuration for this is 2p6.
What is the electronic configuration of neon?
1s2 2s2 2p6
What is the electronic configuration of aluminium?
1s2 2s2 2p6 3s2 3p1
Why do we not know the exact locations of electrons and what is this called?
They move too fast.
The quantum mechanical model.
How many sublevels would an atom with 4 energy levels have?
- The more energy levels, the more sublevels. DO NOT CONFUSE THIS WITH ORBITALS - THE 4th ORBITAL CAN HOLD 7 PAIRS
What is Hund’s rule?
Electrons occupying orbitals of the same energy level will have the maximum number of electrons with the same spin. This is why you half fill the boxes showing sublevels first and then pair up with any remaining electrons.
STRANGER DANGER!!!
What is the Pauli exclusion principle?
If 2 electrons occupy the same sublevel, they have opposite spins. This is shown by fish hook arrows going in opposite directions.
What is the maximum number of electrons in each sublevel?
Energy Max
1 2
2 8
3 18
4 32
5 50
In what order do sublevels fill up and which principle is this?
1s 2s 2p 3s 3p 4s 3d
This is the Aufbau Principle.
What is the short hand for electronic configurations?
Use the noble gasses.
E.g. Sodium - 11 electrons.
[Ne] 3s1
