Electron Arraignment for Elements Above Atomic # 18

Electron Shells

• Periods on the periodic table are similar because they have the same number of electron shells.

• Within these shells there are layers called sublevels', a shell can have between 1 and 4 sublevels.

Sublevels of Electron Shells Sublevel How Many Electrons can it Hold?

s 2 p d f 6 10 14

Electrons Shells and their Sublevels Shell or Period # Sublevels Allowed

1 2 3 4 5 6 7 s s, p s, p, d s, p, d, f s, p, d, f s, p, d s, p

Blocks on the Periodic Table **the period and block an element lives in indicates the sublevel their final electrons are filling, that element will have full shells for all prior blocks.

Aufbau Diagram – unfortunately, sublevels do not always fill in order. You can use the diagram to the right to understand how they fill.

Standard Notation of Fluorine

Number of electrons in the sub level 2,2,5 1 s 2 2 s 2 2 p 5 Sublevels

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How is the electron configuration written?

Each row of an electron configuration table is sort of like a sentence. Each 'sentence' is made up of smaller 'words'. Each 'word' follows this format: • • • The first number is the

energy level

. We can tell right away that an atom of gold contains 6 energy levels.

The lowercase letter is the

sub-shell

. The sub-shells are named s, p, d and f. The number of available sub-shells increases as the energy level increases. For example, the first energy level only contains an s sub shell while the second energy level contains both an s sub-shell and a p sub-shell.

The number in superscript is the

number of electrons in a sub-shell

. Each sub-shell can hold only a certain number of electrons. The s sub shell can hold no more than 2 electrons, the p sub-shell can hold 6, the d sub-shell can hold 10 and the f sub-shell can hold as many as 14.

Example:

• The electron configuration for Nickel would look like: – 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 8

You Try:

• Using your Bohr model of gallium from the energizer, write the full electron configuration for gallium.

– 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 1

One more…

• Write the full electron configuration for palladium.

– 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 8

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Abbreviated vs. Unabbreviated Notation Unabbreviated:

list all sub shells as we did in the previous examples •

Abbreviated:

list the last noble gas prior to the element then all subshells that fall after this: – Example – abbreviated version of palladium: • [Kr] 5s 2 4d 8

Why is this important?

• Understanding the electron configuration of an atom will help us identify what type of ion or compound an atom will typically form.

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Electron Configuration Song

https://www.youtube.com/watch?v=Vb6 kAxwSWgU