Section 11.3

Atomic Orbitals

1. To learn about the shapes of the s, p and d orbitals

2. To review the energy levels and orbitals of the wave mechanical model of the atom

3. To learn about electron spin

Objectives

Section 11.3

Atomic Orbitals

A. The Hydrogen Orbitals

• Orbitals do not have sharp boundaries.

90% boundary

Section 11.3

Atomic Orbitals

A. The Hydrogen Orbitals

• Hydrogen has discrete energy levels.• Called principal energy

levels (electron shells)• Labeled with whole numbers• Energy is related to 1/n2

• En = E1/n2

• Energy levels are closer together the further they are from the nucleus

Hydrogen Energy Levels

Section 11.3

Atomic Orbitals

A. The Hydrogen Orbitals

• Each principal energy level is divided into sublevels.

Hydrogen Energy Levels

– Labeled with numbers and letters – Indicate the shape of the orbital

Section 11.3

Atomic Orbitals

Orbital Designations

Section 11.3

Atomic Orbitals

Orbitals Define the Periodic Table

Section 11.3

Atomic Orbitals

A. The Hydrogen Orbitals

• The s and p types of sublevel

Hydrogen Energy Levels

Section 11.3

Atomic Orbitals

Representation of s, p, d atomic orbitals

Section 11.3

Atomic Orbitals

A. The Hydrogen Orbitals

• Why does an H atom have so many orbitals and only 1 electron? – An orbital is a potential space for an electron. – Atoms can have many potential orbitals.

• s, p, d, f orbitals named for sharp, principal, diffuse and fundamental lines on spectra. Further orbitals designated alphabetically

Hydrogen Orbitals

Section 11.3

Atomic Orbitals

g g gg

f ff

s p d d

Section 11.3

Atomic Orbitals

• Close examination of spectra revealed doublets• Need one more property to determine how electrons

are arranged• Spin – electron modeled as a spinning like a top• Spin is the basis of magnetism

B. The Wave Mechanical Model: Further Development

Electron Spin

Section 11.3

Atomic Orbitals

• Pauli Exclusion Principle (Wolfgang Pauli 1925) - an atomic orbital can hold a maximum of 2 electrons and those 2 electrons must have opposite spins

• When an orbital contains two electrons (of opposite spin) it is said to be full

B. The Wave Mechanical Model: Further Development

Pauli Exclusion Principle

What are the four descriptors that define an energy level / electron’s position in an atom?