Chapter 5: Electrons in Atoms

Section 1: Models of Atoms

Describe the Bohr model of atoms; Define the term quantum; Describe the quantum mechanical model of

the atom and how it relates to probability; and

Describe (and draw) orbitals related to different sublevels.

Students will be able to…

Where did Rutherford leave us...

Rutherford’s model didn’t explain chemical properties

Needed a new model Bohr proposed that electrons orbit

in distinct energy levels Can’t be between levels, but can

jump from one to another Quantum: amount of energy

needed for an electron to jump from one energy level to another

We have a problem…

Neils Bohr(1885-1962)

Scientists found that they can’t base a model for tiny little atoms on the rules for normal-sized stuff

Atoms and subatomic particles act differently◦ Particles act like waves◦ Can’t know velocity and position of electrons

Can calculate probability that electrons are at a given location

Let’s think about this…

Quantum Mechanical Model: determines allowed energies an electron can have and where electrons are likely to be

Energy levels: “layers” where electrons ◦ Numbered◦ Each one gets bigger than previous◦ Can have sublevels

Atomic orbitals: region in space in which there’s a high probability of finding an electron◦ In sublevels◦ Given letters

Atoms are like ogres...

s sublevel◦ one spherical orbital◦ one in every energy level

p sublevel◦ three dumbell-shaped orbitals◦ in all energy levels ≥ 2

Sublevels and orbitals

d sublevel◦ five crazy shapes◦ in all energy levels ≥ 3

f sublevel◦ seven shapes that are really too tough to draw◦ in all energy levels ≥ 4

Sublevels and orbitals

Each energy level gets one more sublevel

Back to the ogres/onions...

Each energy level gets one more sublevel

Each energy level can hold more electrons

Max of 2 e‐ per orbital # of e‐= n2x 2

Back to the ogres/onions...

Describe the Bohr model of atoms? Define the term quantum? Describe the quantum mechanical model of

the atom and how it relates to probability? Describe (and draw) orbitals related to

different sublevels?

Can you….?

Page 132, #1-7 Read Section 2

◦ pages 133-136

Homework