# Bohr Models – Selected Ans

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Bohr Models – Selected Ans
Sodium [11] Carbon [6] Chlorine [17] p+s = 11 p+s = 6 p+s = 17 e-s = 11 e-s = 6 e-s = 17 1st ring = 2 e-s 2nd ring = 8 e-s 2nd ring = 4 e-s 3rd ring = 1 e-s 3rd ring = 7 e-s

Electron Configuration
Unit 2 – Lecture 4

Background Information
Groups = vertical columns Periods = horizontal rows

Describing Orbitals e-s exist in shells surrounding the nucleus
Lewis dot structures – show valence shell of e-s only can be used to show bonding

Describing Orbitals – cont’d
Bohr Models – show basically same info but includes also the other levels used to figure out valence e- further knowledge has shown that e-s actually move in a cloud, taking up more than just rings model to the right is about 70 years out of date!!

Quantum Numbers Quantum #s – describe the “clouds” of e-s
First E Level = “s” up to 2 e-s Second E Level = “p” up to 6 e-s Third E Level = “d” up to 10 e-s …that’s as high as we’re going to go

Quantum Numbers – cont’d
1s(up to 2) 2s(up to 2) Levels fill from lowest (s) to highest (d-for our purposes…) 2p(up to 6) 3s(up to 2) 3p(up to 6) 4s(up to 2) 3d(up to 10) 4p(up to 6) ***the 4th level “s” fills before the 3rd “d” level!!!!!

Quantum #s Examples Hydrogen –
# of e-s = [recall: atoms are neutral] = 1 e-s determine shells will only fill part of the first “s” orbital we note this as “ 1s1 ” meaning 1st s orbital w/ 1 e-

Quantum #s Examples Phosphorous –
# of e-s = [recall: atoms are neutral] = 15 e-s determine shells 15 e-s; fill from bottom up notation: 1s2 2s2 2p6 3s2 3p3

Quantum #s Examples Manganese –
# of e-s = [recall: atoms are neutral] = 25 e-s determine shells 25 e-s; fill from bottom up notation: 1s2 2s2 2p6 3s2 3p6 4s2 3d5

Quantum #s & Periodic Table
Period Indicates Quantum Numbers!!! Just count across the periods…