the electron configuration. write the electron configuration for a variety of atoms and ions relate...
TRANSCRIPT
The Electron Configuration
• Write the electron configuration for a variety of atoms and ions
• Relate the electron configuration of an element to its valence electron(s) and its position on the periodic table.
Additional KEY TermsShorthand notation
NUCLEUS
1s
2s 2p
3s
3p 3d
4s 4p 4d 4f
Quantum Level
Shapes Total Orbitals
1 s 1s = 1
2 s,p 1s+3p = 4
3 s,p,d 1s+3p+5d = 9
4 s,p,d,f 1s+3p+5d+7f = 16
n n types n2
1. Pauli Exclusion Principle• Electrons are constantly spinning which creates
a magnetic field• Two electrons can occupy the same orbital only
if they have opposite spins
Each orbital (m) of a shape can hold two spinning electrons (s)
n = 1
1s2
n = 22s22p6 n = 33s2 3p6 3d10
OLD way
NEW way
2e- 8e- 18e-
8e-
8e-
2e-
Quantum Level
Shapes Total orbitals e- capacity
1 s 1 = 1 2
2 s,p 1+3 = 4 8
3 s,p,d 1+3+5 = 9 18
4 s,p,d,f 1+3+5+7 = 16 32
n n types n2 2n2
2. Aufbau Principle
Unexcited electrons fill the lowest, most stable, energy orbital available – ground state.
Notice: as you get further from the nucleus the energy
differences are similar enough to mess-up the
“order”
3. Hund ruleElectrons must enter empty orbitals of equal energy first before joining occupied orbitals.
The “get your own room” principle – no one wants a bunkmate
Electron Configuration
Orbital Box Diagrams
1s 2s 2p 3s 3p 3d4s
These are the two ways of representing electron location – we will focus on Electron Configuration
Periodic Table shows orbital filling for the electron configuration of elements.
Draw orbital box and electron config for carbon.
C: 1s2 2s2 2p2
1s 2s 2p
Draw orbital box and electron config for Mg.
Mg: 1s2 2s2 2p6 3s2
1s 2s 2p 3s
First ask yourself “how many total electrons,” then
put them in their correct orbitals
Draw electron config for germanium.
Ge – atomic number 32
Ge: 4s2 3d10 4p2
• Shorthand notation using noble gas “kernels.”
Ge: [Ar] 4s2 3d10 4p2
1s2 2s2 2p6 3s2 3p6
[Ar]
12345
Write the shorthand configurations for Mn and Ag.
Mn: [Ar] 4s2 3d5 Ag: [Kr] 5s2 4d9
Find the last filled Noble Gas to use as the kernel
• Valence configuration includes the electrons in the outer-most or highest quantum level (n).
F = 9 electrons
1s2 2s2 2p5 Valence configuration - 2s2 2p5
Ge = 32 electrons
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p2
Valence configuration - 4s2 4p2
It’s not just the last ones, but the total electrons in the outer
quantum level
F-1 = 9 electrons + 1 gained
The ION configuration is 1s2 2s2 2p6
Fe+2 = 26 electrons – 2 lost
The ION configuration is 1s2 2s2 2p6 3s2 3p6 3d6
Valence electrons are removed from the highest quantum level
1s2 2s2 2p5
1s2 2s2 2p6 3s2 3p6 4s2 3d6
Some exceptions to the rule:
• Half-filled and completely filled orbitals have extra stability
• Atoms will “promote” electrons to improve overall stability
Electron Promotion
Look for configurations ending in “p2” ,“p5” OR “d4” ,“d9” - one electron from being half or
complete filled…”
Cr: [Ar] 4s2 3d4 Cu: [Ar] 4s2 3d9
Actual configurations:Cr: [Ar] 4s1 3d5 Cu: [Ar] 4s1 3d10
4s 3d 4s 3d
Electron promotion accounts for multiple ionization states (Fe+2, Fe+3…)
CAN YOU / HAVE YOU?
• Write the electron configuration or orbital box diagrams for a variety of atoms and ions
• Relate the electron configuration of an element to its valence electron(s) and its position on the periodic table.
Additional KEY TermsShorthand notation