Atomic structure part 4 quantum mechanics Quantum mechanics and the atom… sound like fun… Well… if fun is like hitting you hand with a hammer…

Atomic structure part 4quantum mechanics

Quantum mechanics and the atom… sound like fun… Well… if fun is like hitting you hand with a hammer…

Quantum physics and the atom

• What subatomic particle (p+, n, e-) is responsible for “all” normal chemical reactions?

• Right.• The quantum mechanical model of the atom

focuses on the electron and how it behaves in the atom…

• yarp!

Quantum numbers and the electron

• This model of the atom has the electrons on “rings” called energy levels.

• NOT GOOD ENOUGH!!!• It has been found electrons

are doing much more complicated things…

• yarp

p+

n

So we have quantum numbers

• Quantum numbers are a way of determining where a specific electron in an atom is….

• How is that electron moving?• How much energy does it have?• It is pretty much nerdy battleship for

electrons.• yarpy

Quantum #’s (4 of them)

• 1. principle Quantum # “n” tells you what energy level an electron is on.

• “n” ranges from 1-7Though it can go higher

• Higher the number• Typically further from the nucleus• Typically have more energy• yarp

That is what these rings are showing you

• How many energy levels?

• Which one has e- furthest from nucleus?

• Which one has e- with the least amount of energy?

p+

n

• 2. second quantum # = the general orbital shape (or flight path) the electron is moving as the e- moves around the nucleus.

• The “shape” not a physical thing… it is the repeated path of the electron!

• s = sphere• yarp

• p = dumbbell

• d = complex

• f = very complex• yarp

Adding a layer… energy levels, shapes and electrons

Letter Shape # flight paths on 1 energy level

Max # electrons

Looky look!!!! Notice anything?# of flight paths and shapes??

The third quantum number

• This quantum # locates an electron with the orientation of an orbital

• px py pz

• These are called• ORBITAL SUBLEVELS• yarp

Put the 3 quantum to work…

• 4d• 5s• 2px

• 6py

• What….• Has the most energy?• Closest to the nucleus?• Making a sphere?• Shows the 3rd quantum

number?• Which one has a

dumbbell sublevel on the y axis?

• Any others Mr. S?• yarp

the 4TH quantum number

• This is the spin quantum number• Like our planet… each electron rotates/spins

around it’s own axis.• Electrons paired up in the same orbital

sublevel spin opposite of each other• Up and down spin• Clockwise and counter clockwise spins• yarp

How do we show spin???• Up and down arrows… vectors…

• Why don’t you show some examples of how this works??? Dare to compare the electrons!

• 1s↑ 4pz ↓ 5f↑ 5d↑

• Ask your questions Mr. S…. • yarp

Why don’t electrons….

• Well… collide and destroy all matter?

• What does the first quantum # tell you???

• So won’t there be overlap???

• Why no collide????• yarp

The shapes electrons take

• All of the shapes we have talked about…• It is all about keeping the negative charge of

electrons as far away from each other as possible

• px py pz • Y to the arp

Atomic structure part 4

Putting the box diagrams into the fun of the funness of quantum numbers

Find the 4 quantum #s in this…

1s

7s

2s

3s

4s

5s

6s

2p

3p

4p

5p

6p

7p

3d

4d

5d

6d

4f

5f

Atom nucleus

Increasing energy

Example 1 hydrogen

1s

7s

2s

3s

4s

5s

6s

2p

3p

4p

5p

6p

7p

3d

4d

5d

6d

4f

5f

Atom nucleus

Increasing energy

Example 2 helium

• Pauli exclusion principle = no more than 2 e- can be in the same orbital sublevel. They spin opposite of each other

• yarp

1s

7s

2s

3s

4s

5s

6s

2p

3p

4p

5p

6p

7p

3d

4d

5d

6d

4f

5f

Atom nucleus

Increasing energy

Example 3 Beryllium

• Auf Bau principle = you build up by filling lowest energy orbital sublevels first before move to higher energy sublevels

• yarp

1s

7s

2s

3s

4s

5s

6s

2p

3p

4p

5p

6p

7p

3d

4d

5d

6d

4f

5f

Atom nucleus

Increasing energy

Example 4 carbon

• Hunds rule = orbital sublevels of equal energy each get 1 e- before pairing up in the same sublevel

• yarp1s

7s

2s

3s

4s

5s

6s

2p

3p

4p

5p

6p

7p

3d

4d

5d

6d

4f

5f

Atom nucleus

Increasing energy

Example 5 Bromine

• Now, use the 5 to teach them electron shorthand configuration

• yarp1s

7s

2s

3s

4s

5s

6s

2p

3p

4p

5p

6p

7p

3d

4d

5d

6d

4f

5f

Atom nucleus

Increasing energy