OCR A 2.2.1 Electron Structure

atomic orbitals

-a region around the nucleus that can hold up to 2 electrons

-with oppo spin

shells

-energy levels

-energy increases as shell number increases

principal quantum number

-(n)

-shell/energy level number

how many subshells in electron shell

4

electron subshells

-s; 1 orbital, holds 2 e (1s)

-p; 3 orbitals, holds 3 × 2 = 6 e (2s, 2p)

-d; 5 orbitals, holds 5 × 2 = 10 e (3s, 3p, 2d)

-f; 7 orbitals, holds 7 × 2 = 14 e

relationship between shell number and nucleus

higher the shell number, further away it is from nucleus and has higher energy

s orbital shape

-1 orbital

-e cloud within shape of sphere

-e move anywhere within sphere

p orbital shape

-3 orbitals

-electron cloud within shape of dumbbell

-3 separate dumbbells at right angles to each other

-e move anywhere within shape

spin pairing

-when 2 e occupy 1 orbital, they spin in oppo direction

-as e are -ve they repel

-oppo spin counteracts repulsion

orbital filling rules

-fill in order of increasing energy; 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² (4s fills before 3d)

-orbital w/ same energy singly filled, then dbly; prevents repulsion between paired e

electron config of ions

-when filled 4s energy level is higher than 3d

-4s empties before 3d