Levels/Shells

Principal Quantum Number (1-7)

(2 x level2) determines the amount of electrons that can fit into that energy

level

Electron Organization

Sublevels/Subshells

The specific cloud shape within the level.

s p d f

1 s shape

3 p shapes

5 d shapes

7 f shapes

Orbitals

The specific area within the cloud shape.

Each orbital holds 2 e- max.

s = 1 orbital, holds up to 2 e-

p = 3 orbitals, holds up to 6 e-

d = 5 orbitals, holds up to 10 e-

f = 7 orbitals, holds up to 14 e-

Rules for e- filling in the atom

1.Aufbau Principle – an atom fills with e- in a specific order to achieve lowest energy.

2. Pauli’s Principle – no 2 e- in an orbital can have the same spin. (why only 2 e- max)

3. Hund’s Rule – In a sublevel, each orbital gets an electron before the electrons pair up. Creates lower energy.

Orbital Notation(diagrams)Shows orbitals (circles,lines,boxes) and position of electrons (arrows)

 Ex: Carbon 6 e-

1s 2s 2p 

Electron Configuration

Gives the level, sublevel, and number of electrons within an atom

Ex: Carbon 6 e-

1s2 2s2 2p2

Sn 50 e-

1s22s22p63s23p64s23d104p65s24d105p2

Noble gas notation (shorthand) puts brackets around the noble gas that completed the row above the element

[Kr] 5s24d105p2

Valence Level Level holding the outer most e- in

atom

8 valence e- max

Determines the element’s properties

 

Electron Dot Diagrams

- Element symbol with dots (valence e-)

- 8 dots max, grouped by orbitals

EX: Lithium 3 e- Bromine 35 e-

1s22s1 [Ar]4s23d104p5

Li Br