Electron Configuration Flashcards
What is an atomic orbital?
An atomic orbital is a region within an atom, around the nucleus, that can hold up to 2 electrons with opposite spins
What is a shell/energy level?
A shell is a group of atomic orbitals with the same principal quantum number,n. The shell closest to the nucleus has a principle quantum number of 1 and has the lowest energy.
What is a sub-shell?
Within each shell electrons and arranged into sub-shells. A sub-shell is a group of the same type of atomic orbitals within a shell.
Increase in a shell
With each increase a new sub-shell is added
-n = 1 ->S
-n = 2 -> S, P
-n = 3 -> S, P, D
S sub-shell
1 orbital, holding 2 electrons
P sub-shell
3 orbitals, 6 electrons (each holds 2)
D sub-shell
5 orbitals, 10 electrons (each holds 2)
F sub-shell
7 orbitals, 14 electrons (each holds 2)
Shell -> No. of orbitals, electrons and sub-shells
Shell 1 - 1 orbital, 2 electrons, S
Shell 2 - 4 orbitals, 8 electrons , S + P
Shell 3 - 9 orbitals, 18 electrons, S + P + D
Shell 4 - 16 orbitals, 32 electrons, S + P + D + F
Order of how electrons fill orbitals
1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d10, 4p6, 4d10, 4f14
Property of electrons - boxes
Each electron is negative, expected to repel each other. 2 spins ‘up’ or ‘down’
Boxes per sub-shell
S - 1 box for 1 orbital
P - 3 boxes for 3 orbitals
D - 5 boxes for 5 orbitals
Why are Cr and Cu exceptions?
Half full 4s sub-shell but fuller 3d sub-shell because it makes it more stable
What are transition metals?
D-block elements that form ions with an incomplete d sub-shell. Losing their 4s first when forming positive ions
Expeditions to the transition metal rules
Zinc and Scandium. Zinc has a complete 3d sub-shell even after losing electrons (loses from 4s first) and scandium has an empty 3d sub-shell
