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The arrangement of electrons within the orbitals of an atom
Consists of numbers letters, and superscripts
◦ Energy Level – a number (1, 2, 3, etc…)
◦ Sublevel – a letter (s, p, d, or f)
◦ Number of electrons – a superscript number
ANALOGY:
Driveway, types of cars, how many seats

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Step 1: Determine how many electrons
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Practice:
◦ Na
◦ O
◦ Li
◦ B

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Step 2: Fill the orbitals with the correct number electrons following the pattern below

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 s subshell has 1 orbital and can hold 2 electrons p orbital has 3 orbitals and can hold 6 electrons d has 5 orbitals – 10 electrons f has 7 orbitals – 14 electrons
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What is the maximum number of electrons an orbital can have??

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1
2
2
1
2
2
1
2
2
2
2
2
6
1

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By following this order of electrons occupying the lowest energy orbital first
Electrons are lazy!

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Fill empty orbitals first
Electrons do not want to share!
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Carbon has the electron configuration:
1s 2 2s 2 2p 2 , based on Hund’s Rule which one is correct?
_ 1s _ 2s _ _ _ 2p
_ 1s _ 2s _ _ _ 2p

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Electrons have to have
spins
Electrons have either an Up spin or a Down spin
◦ Up and Down are always paired together, never Up-
Up or Down-Down

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The order for filling the sublevels: 1s, 2s, 2p,
3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p,
7s, 5f, 6d, 7p
How many electrons can go in a s sublevel? p? d? f?

1s 2s 2p
1s 2s 2p 3s 3p
1s 2s 2p 3s 3p

1.
2.
3.
4.
Write the electron configuration for Cl
Write the electron configuration for O
What is the lowest energy level that can have a p orbital?
Which element is represented by the following electron configuration?
1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 4
** What questions do you have for me? What do you need more help with? **

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Practice Worksheet – due tomorrow!