Orbital Notations and Electron Configurations

1

2

N = principle energy level

2N2 = # of e- in N

Finding Orbital Quantum #s on the Periodic Table

D Block

F Block

1234567

3456

1234567

45

P BlockS Block

Orbital Notation

Shows all four quantum numbers for every electron in the atom.

A box or line is one orbital.An arrow is one electron.Spin is designated as “up” or “down”.

Orbital Notation for Silicon Silicon has 14 electrons, so you will draw 14

arrows.

1s 2s

2p

3s

3p

More Examples:

1s 2s 2p 3s

Magnesium

1s 2s 2p 3s 3p 4s 3d

1s 2s 2p 3s 3p

Copper

Chlorine

Electron Configurations

7

Shorthand versions of orbital notations.

Does not indicate the magnetic or spin quantum numbers.

Tells the total number of electrons in each SET of orbitals.

Writing an Electron Configuration

8

Write the electron configuration for Neon.

11s222s222p6

Principle Quantum NumberPrinciple Quantum NumberOrbital Quantum NumberTotal Number of Electrons

Your Turn

9

Write the electron configuration for Potassium.

Write the electron configuration for Copper

Write the electron configuration for Bromine

Answers

10

Potassium

1s22s22p63s23p64s1

Copper

1s22s22p63s23p64s23d9

Bromine

1s22s22p63s23p64s23d104p5

Excited State Electrons

11

You can also draw and recognize elements with electrons in the excited state from an electron configuration.

For example: What element is shown?

1s22s22p63s13p1

What did you answer?

12

This is NOT Aluminum (Al), this is Magnesium (Mg) in the excited state!!

Why? Look at the 3s sublevel…

1s22s22p63s13p1

Configurations for Ions

13

Add or remove the correct number of electrons and write the new configuration.

Cu+2 ion

1s22s22p63s23p64s23d7

Not 9, because the ion lost 2 electrons (it’s configuration now looks like Cobalt’s.)