Quantum numbers

Where’s My Electron???

The Major Players

• Werner Heisenberg

• Heisenberg Uncertainty Principle

• Electron Density

• Erwin Schrödinger

• Wave functions ()

• Atomic Orbital

• Quantum Numbers

Werner Heisenberg

• Tried to locate a subatomic particle that behaves like a wave.

Heisenberg Uncertainty Principle

It is Impossible to know the exact momentum and position of a particle with any certainty.

Electron Density

• Gives the probability of finding an electron in a particular region of an atom

Erwin Schrodinger

• Created wave functions

Wave Functions

Complicated mathematical expressions used to describe the probability of finding an electron around a nucleus.

Radial Distribution CurveOrbital

Orbital (“electron cloud”)

–Region in space where there is 90% probability of finding an e-

Quantum Numbers-zip codes for electrons-

4 Types of Quantum #s

1. Principal (n)• Distance from nucleus

2. Angular Momentum (l)• Orbital Shape

3. Magnetic (ml)

• Orientation in space

4. Spin (ms)

• Rotational Spin

PRINCIPAL QUANTUM NUMBER

(n)

Energy level / shell

Size of the orbital

n2 = # of orbitals in the energy level

Angular Momentum / Azimuthal

(l)

s p d f

Energy sublevel / subshell

Shape of the orbital

MAGNETIC (ml)

Orientation of orbital

Specifies the exact orbitalwithin each sublevel

px py pz

SPIN (ms)

Electron spin +½ or -½

–An orbital can hold 2 electrons that spin in opposite directions.

Quantum Numbers-zip codes for electrons-

4 Types of Quantum #s

1. Principal (n)• Distance from nucleus

2. Angular Momentum (l)• Orbital Shape

3. Magnetic (ml)

• Orientation in space

4. Spin (ms)

• Rotational Spin

• n = # of sublevels per level

• n2 = # of orbitals per level

• Sublevel sets: 1 s, 3 p, 5 d, 7 f

• Orbitals combine to form a spherical

shape, which defines the “electron

cloud.”

2s

2pz2py

2px

Let’s see how it works.

Questions

How many orbitals are in the following sublevels?

3p2s4p3d4f

3: px, py, pz

1: s3: px, py, pz

5: dxy, dyz, dxz, dx2-y2, dz2

7: Don’t worry, just know it

Questions

How many sublevels are contained in each of the following energy levels?

n = 1n = 2n = 3n = 4

1, the s sublevel2, the s and p sublevels3, the s, p, and d sublevels4, the s, p, d, and f sublevels

Questions

What is the maximum number of electrons that can go into each of the following sublevels?

4s 3p 4s 3d

4p 5s 4f 5p

2e- 6e- 2e- 10e-

6e- 2e- 14e- 6e-