Configurations, Spin, and Ionization Energy
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Transcript of Configurations, Spin, and Ionization Energy
Configurations, Spin, and Ionization Energy
Filling Order of Orbitals in Multielectron Atoms
1s22s22p63s23p64s23d104p65s2…
Writing e- Configurations
Oxygen (8 e-)
Spectroscopic Notation: 1s22s22p4
Orbital Box Notation:
1s 2s 2p
Isoelectronic Series Isoelectronic = same e- configuration Properties within series are affected by Z
e.g., ion size decreases as Z increases
Mg2+ Na+ O 2-F-
increasing nuclear charge (Z)
10 e- in each: 1s22s22p6
Z = +12 +11 +9 +8
Ionization Energy
E of e- removal from an atom or ion in the gas phase
A(g) A+(g) + e- ; E = IE1 = 1st IE
A+(g) A2+(g) + e- ; E = IE2 = 2nd IE
Always positive. Why?
Trends in First IEincreases
decreases
Ionization Energy
Whatever increases E of e- decreases IE Down a group: larger n ˝ lower IE Across a period: increasing nuclear charge
increases IE several anomalies
IE1 Values for First 20 Elements (Problem 4)
Why is IE1(N) > IE1(O)?
O: 1s22s22p4
N: 1s22s22p3
e- - e- repulsion (spin pairing E) in the first 2p orbital makes e- a little easier to remove than unpaired e- in a N 2p orbital
Is 2s 2p
High IE Values
Be: 1s22s2 ; B: 1s22s22p1
Elements with filled shells (noble gases) Elements with filled subshells
IEBe > IEB
Elements with half-filled subshells IEN > IEO