Unit 4:The Electron

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Unit 4The Electron

• Part 4 Periodic Table Short Form

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Using the Periodic Table to determine Elec
Configuration
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Periodic Table to remember order
Sublevel (s,p,d,f) by columnsEnergy Levels by
row (1,2,3,4,5,6,7) except d(row minus 1) f(row
minus 2)
X 1s22s22p63s23p4 total of 16 e-
p6
Y 1s22s22p63s23p6 4s23d104p6 5s1 total of36
e-
s1
s2
s2
p1
p2
p3
p4
p5
1
2
X
3
4
Y
5
6
7
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Example 1 Helium
He is atomic 2 which means 2p 2e- 1energy
level s2sublevel 2electrons)
s2
Ans 1s2
1
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Example 2 Lithium

• Li (atomic 3) (means 3p 3e-)
• 2nd energy levels 1s 2ssublevels
  21electrons

Ans 1s22s1
s2
s1
1
2
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Example 3 Beryllium
Be (atomic 4) (means 4p 4e-) 1,2energy
levels ssublevel 22electrons
1s22s2
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Example 4 Silicon

• Si (atomic 14) (means 14p 14e-)
• 1,2,3energy levels s,psublevels
  22622electrons)

1s22s22p63s23p2
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How About a Tougher One???

• An atom of gold has 79 electrons arranged in the
  following order
• 1s22s22p63s23p64s23d104p65s24d105p66s24f145d9
• Golds electrons require six energy levels.
  (Sixth quantum number.)
• It has 2 electrons in its highest level.
• Superscripts must add up to the atomic number of
  the element. (p e-)
• Gold has 79 p and 79 e
  (22626210621062149)

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Short Form Orbital Diagrams

• Two more useful models to show the location of
  the all important valence (or outer) electrons
• the Short Form of Elec Config
• And Orbital Diagrams

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Electron ConfigurationShort Form

• Notice that large portions of each electron
  configuration is repetitive.
• To write an electron configuration in short form
• 1. Find the element on the periodic table and
  back up to the previous noble gas.
• 2. Write the symbol for the noble gas in
  brackets, then continue with the remainder of the
  electron configuration.

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Electron ConfigurationShort Form

• Calcium
• Atomic Number 20
• Electron Configuration Long Form
• 1s22s22p63s23p64s2
• Electron Configuration Short Form
• Ar4s2

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Thank you, may I have another?

• Tin
• Atomic Number 50
• Electron Configuration Long Form
• 1s22s22p63s23p64s23d104p65s24d105p2
• Electron Configuration Short Form
• Kr5s24d105p2

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So, what if it is a noble gas?

• Neon
• Atomic Number 10
• Electron Configuration Long Form
• 1s22s22p6
• Electron Configuration Short Form
• He 2s22p6