1. The Quantum Mechanical Model
Energy is quantized. It comes in chunks.
A quanta is the amount of energy needed to move from one energy level to another.
Since the energy of an atom is never “in between” there must be a quantum leap in energy.
Erwin Schrodinger derived an equation that described the energy and position of the electrons in an atom

2. The Quantum Mechanical Model
The quantum mechanical model is a mathematical solution
It is not like anything you can see.

3. The Quantum Mechanical Model
Has energy levels for electrons.
Orbits are not circular.
It can only tell us the probability of finding an electron a certain distance from the nucleus.

4. QM model - Modern View The atom is mostly empty space Two regions
1. Nucleus- protons and neutrons
2. Electron cloud- region where you might find an electron

5. Other particles
Proton - positively charged pieces 1840 times heavier than the electron – by E. Goldstein
Neutron - no charge but the same mass as a proton – by J. Chadwick

6. Subatomic particles Relative mass Actual mass (g) Name Symbol Charge
Electron e- -1 1
9.11 x 10-28
Proton p+ +1
1840
1.67 x 10-24
Neutron n0
1840
1.67 x 10-24

7. Size of an atom Nucleus tiny compared to atom
If the atom was the size of a football stadium, the nucleus would be the size of a marble.