More Electron Arrangement!

Examples:

Se               1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p4

Sn               1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p2

Hg               1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10

HOEL (Highest Occupied Energy Level):  energy level furthest from the nucleus that contains at least one electron

How to determine this using electron configuration?

~ largest non-exponent number

Se               1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p4                                               HOEL = 4

Sn               1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p2                           HOEL = 5

Hg               1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10       HOEL = 6

Valence Electrons:  electrons in the HOEL

How to determine this using electron configuration?

~ add up exponents of terms in HOEL

Se               1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p4
HOEL = 4              Valence electrons = 2 + 4 = 6

Sn               1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p2
HOEL = 5              Valence electrons = 2 + 2 = 4

Hg               1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10
HOEL = 6              Valence electrons = 2

Noble Gas Configuration:  shortcut for electron configuration

How is it written?

~ [ symbol for noble has closest to element with lower atomic # ]

~ [after brackets] next number is the period that the element is located in

~ after that number, write “s”

~ continue electron configuration in diagonal rule order until appropriate # of
electrons is reached

*NOTE:  ending of electron configuration and noble gas configuration should be the same*

Se               1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p4
[Ar] 4s2 3d10 4p4

18    20       30       34

Sn               1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p2

[Kr] 5s2 4d10 5p2

36      38       48      50

Hg               1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10
[Xe] 6s2 4f14 5d10

54     56       70       80

Orbital Notation:  drawing of how electrons are arranged in orbitals; will only need to do this for the HOEL

*NOTE:        ___  = orbital                  h or i  =  electrons

Se               1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p4                            hi     hi h  h_
4s        4p

Sn               1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p2        hi     h  h  __
5s        5p

Hg               1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10                hi

6s

Dot Diagrams:  symbol represents nucleus and non-valence (“inner-shell”) electrons;  dots around symbol represent valence electrons