Bohr Models and Electron Configuration

Compare and contrast the Bohr Planetary Model and the Schrödinger Quantum Mechanical Model

Bohr has energy levels in set rings/orbitals, Schrödinger has electrons in clouds of probability (still had energy levels, but also sublevels & orbitals)

Bohr Model for Helium-4

Bohr Model for Oxygen-16

Bohr Model for Silicon-28

14 p+

14 nº

1st level: 2

2nd level: 8

3rd level: 4

Bohr Model for Calcium-40

20 p+

20 nº

1st level: 2

2nd level: 8

3rd level: 8

4th level: 2

How does knowing the "blocks" on the Periodic Table help you determine the configurations?

- Blocks tell you ending configuration for neutral ground state atom

- rows help you determine ending of each energy level

- columns tell you the # of electrons in the ending configuration

What is the ending configuration for every Noble Gas (except He)?

Ne: 2p6

Ar: 3p6

Kr: 4p6

Xe: 5p6

Rn: 6p6

How many electrons can each sublevel hold?

s- 2

p- 6

d- 10

f- 14

Aufbau Principle

An electron occupies the lowest-energy orbital that can receive it

Pauli Exclusion Principle

when you have a pair, you have opposite spins

Hund's Rule

spread out e- in a sublevel before you split up

How to find the electron configuration of ions

cation: move 2 columns back

anion: move 2 columns forward

Copper's electron configuration

[Ar] 4s1 3d10

Chromium's electron configuration

[Ar] 4s1 3d5

Why do copper and chromium have a different observed electron configuration than expected?

fully & 1/2 filled sublevels are stable, anything else is not. Chromium alters so both 3d & 4s are filled, copper alters so 3d is full & 4s is 1/2 full.

Where is more practice?

The review in Week 9, warmups

Orbital

energy level

a region of an atom in which electrons of the same energy are likely to be found

sublevel

An atomic orbital, or collection of atomic orbitals, that occupy a principal energy level and are called s, p, d, and f.

total electrons in the 1st energy level

2

total electrons in the 2nd energy level

8

total electrons in the 3rd energy level

18

total electrons in the 4th energy level

32

total orbitals in the s sub-level

1

total orbitals in the p sub-level

3

total orbitals in the d sub-level

5

total orbitals in the f sub-level

7

max occupancy of the s-sublevel

2 e-

max occupancy of the p sub-level

6 e-

max occupancy of the d sub-level

10 e-

max occupancy of the f-sublevel

14 e-