ATOMIC STRUCTURE

Electron Configuration

Building the Atom

ATOMIC STRUCTURE Remember… Atomic Number (Z) : the number of protons in the nucleus of the atom. Mass Number (A) : the number of protons and neutrons in the nucleus of the atom. Neutron Number (N) : A - Z = N

ATOMIC STRUCTURE LOCATION OF ELECTRONS IN THE ATOM: • Electron Cloud

• Energy Levels

• Sublevels

• Orbitals

ATOMIC STRUCTURE LOCATION OF ELECTRONS IN THE ATOM: • Sublevels have (degenerate states) that we call orbitals. These sublevels are named s, p, d, f, g, etc. The energy level determines the number of sublevels...

ATOMIC STRUCTURE LOCATION OF ELECTRONS IN THE ATOM:

Sublevels: s- one orbital p- three orbitals d- five orbitals f- seven orbitals Etc...

ATOMIC STRUCTURE LOCATION OF ELECTRONS IN THE ATOM:

It turns out, in each orbital, there can be a maximum of two electrons. So... s- 2 electrons total p- 6 electrons total d- 10 electrons total f- 14 electrons total

ATOMIC STRUCTURE Orbital diagrams and electron configurations

Orbital diagrams help show how the electrons are distributed within the sublevels.

1s NOTICE THAT WHEN ELECTRONS PAIR THEY HAVE OPPOSITE SPINS.

ATOMIC STRUCTURE

PAULI EXCLUSION PRINCIPLE...

No two electrons can have the same quantum numbers or no more than two electrons can be found in any given orbital.

ATOMIC STRUCTURE

HUND’S RULE: the most stable arrangement of electrons

is that with the maximum number of unpaired electrons, all with the same spin direction.

In other words…electrons don’t pair until they have too!

ATOMIC STRUCTURE

Orbital Diagrams

1s 2s 2px 2py 2pz

3s

etc...

What element is this????

ATOMIC STRUCTURE   Another way to write this is by using

electron configuration notation

1s22s22p63s2

ATOMIC STRUCTURE

ORDER OF CHOICE:

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

Why? Energy of some orbitals overlap higher orbitals.

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ATOMIC STRUCTURE

Let’s practice… Assignment: Electron Configuration Level One and Two • Electron Configuration Wkst

ATOMIC STRUCTURE Orbital diagrams and electron configurations

Orbital diagrams help show how the electrons are distributed within the sublevels.

1s NOTICE THAT WHEN ELECTRONS PAIR THEY HAVE OPPOSITE SPINS.

ATOMIC STRUCTURE

Orbital Diagrams

1s 2s 2px 2py 2pz

3s

etc...

What element is this????

ATOMIC STRUCTURE   Another way to write this is by using

electron configuration notation

1s22s22p63s2

ATOMIC STRUCTURE   Another way to write this is by using

noble gas notation

[Ne]3s2

Since Ne has a configuration of 1s22s22p6

ATOMIC STRUCTURE

Let’s practice… Valence Electron Configuration

ATOMIC STRUCTURE

Connections: Do you see any relationship between the electron configuration and where the element is located on the Periodic Table?

ATOMIC STRUCTURE

You should be able to… • Write the electron configuration • Draw the orbital diagram • Write the noble gas notation • And predict the element

ATOMIC STRUCTURE

Assignment: • Electron Configuration Wkst 2