1. Electrons in Atoms
Ch. 13

2. 13-1 Models of the Atom Dalton—Billiard ball model
JJ Thomson—Plum Pudding Model
Rutherford—Gold Foil Experiment

3. Niels Bohr Energy levels
Like a ladder, steps, or an elevator (can’t stand between floors
Quantum: the amount of energy an electron needs to make a jump between energy levels

4. The Bohr model of the atom.
Ground State: lowest possible energy levels
Excited State: when the atom absorbs energy so that its electrons are boosted to higher energy levels

5. Quantum Mechanical Model
No exact path an electron takes around the nucleus—electron cloud
Probability or likelihood of finding an electron in a certain position
Orbitals: a region of an atom in which there is a high probability of finding electrons
Each orbital can have 2 electrons

6. Quantum Model

7. Locations of Electrons in Atoms
n = principal quantum number = energy level
An energy level is subdivided into sublevels.
Sublevels are subdivided into orbitals.
An orbital can hold a maximum of 2 electrons or 1 pair of electrons.
Sublevels: s, p, d, f

8. s-orbital (spherical)
Every energy level has an s-orbital.
Only one per energy level
p-orbital (peanut)
The 1st p-orbital is found in the 2nd energy level and beyond.
There are 3 different p-orbitals (px, py, pz)

9. Diagram of principal energy levels 1 and 2.

10. d-orbital (4-leaf clover)
The 1st d-orbital is found in the 3rd energy level and beyond.
There are 5 different d-orbitals.
f-orbital (flower)
The 1st f-orbital is found in the 4th energy level and beyond.
There are 7 different f-orbitals.

12. ENERGY LEVEL 1 2 3 4
SUBLEVELS s s, p
s, p, d
s, p, d, f

13. Let’s Review
What’s the maximum number of electrons in the 1st energy level?
What’s the maximum number of electrons in the 2nd energy level?

15. Partial electron configurations for the elements potassium through krypton.

16. Electromagnetic Spectrum
Visible spectrum:
sunlight (white light) passes through a prism
Visible to the human eye
Wavelength: the distance between two identical points on the wave
Frequency: the # of wavelengths that pass a certain point in a given period of time

17. The wavelength of a wave.

18. Photons of red and blue light.

20. Colors and wavelengths of photons in the visible region.

21. An excited lithium atom emitting a photon of red light to drop to a lower energy state.

22. The color of the photon emitted depends on the energy change that produces it.