Electron Configurations Unit 3. What are electron configurations? According to the wave mechanical model, the electrons in an atom move around in the.

Electron Configurations

Unit 3

What are electron configurations?

According to the wave mechanical model, the electrons in an atom move around in the orbitals surrounding the nucleus.

There are 7 orbitals! They are numbered 1 – 7!

Each orbital has sublevels!

Sublevels!

They are labeled s, p, d, and f!Each sublevel has a different shape to it!

s - sublevel

p Sublevel

d - sublevels

f - sublevels

Each sublevel has a certain # of “rooms” that 2 electrons reside in.

s has 1 “room”p has 3 “rooms”d has 5 “rooms”f has 7 “rooms”

How many electrons fit in each sublevel total?

Electron Configurations

Are a way of writing out where all the electrons are in an atom.

It specifies the orbital, sublevel, and how many electrons are in the sublevel.

Order of filling

Rules for writing electron configurations

Pauli exclusion principleEach “room” can hold a maximum of 2

electrons, but they must be spinning in opposite directions.

Aufbau PrincipleElectrons enter orbital in order of increasing

energy.Hund’s Rule

One electron must fill each “room” in a sublevel before there can be 2.

Examples

Nitrogen1s22s22p3

Iron1s22s22p63s23p64s23d6

Exceptions to the rules.

Chromium 1s22s22p63s23p64s13d5

Molybdenum

1s22s22p63s23p64s23d104p65s14d5

Tungsten

1s22s22p63s23p64s23d104p65s24d105p66s15d5

Copper 1s22s22p63s23p64s13d10

Silver 1s22s22p63s23p64s23d104p65

s14d10

Gold 1s22s22p63s23p64s23d104p65

s24d105p66s15d10

The Periodic Table and Noble Gas Configurations

Noble gas configurations are a short hand way of writing electron configurations & the Periodic Table can be used to help you write them!

Let’s try some!

Nitrogen Electron configuration - 1s22s22p3

Noble Gas configuration – [He] 2s22p3

IronElectron configuration - 1s22s22p63s23p64s23d6

Noble Gas configuration – [Ar] 4s23d6