1. Electrons
&
Atoms

2. Quantum Mechanical Model
Electrons: probabilities vs. points of matter
The probability of finding an electron within a space can be represented by a fuzzy cloud. These shapes are where scientists believe the electrons will stay 90% of the time.

3. ENERGY LEVELS
The model designates energy levels of electrons by principal quantum numbers. Each quantum number refers to a major or principal energy level in the atom (n=1,2,3,4..)

4. ENERGY SUBLEVELS
Within each principal energy level, the electrons occupy energy sublevels. (They are not ORBITS because the electron is not confined to a fixed circular path.)
Because electrons within the sublevels occupy specific cloud-shaped regions, the cloud shapes are called atomic orbitals. The atomic orbitals are denoted by letters (s, p, d, f, )

5. QM Electron Structure Principal Energy Level # of Sub-Levels Sublevels
(# orbitals within a given sublevel)
# of Electrons in Principal Energy Level
(n=1) 1
s(1)
1x2=2
2n2=2
(n=2) 2
s(1), p(3)
(1+3)x2=8
2n2=8
(n=3) 3
s(1), p(3), d(5)
(1+3+5)x2=18
2n2=18
(n=4) 4
s(1), p(3), d(5), f(7)
( )x2=32
2n2=32

6. Key Things to Remember
At most, only __ electrons exist in any single orbital.
An orbital within a higher energy level is larger than the same type of orbital for a lower energy level (i.e. the 3s orbital is larger than the 2s orbital which is larger than the 1s orbital).
Electrons in _____ energy levels are further from the nucleus.
The principal quantum number (energy level) =
# sublevels within that principal energy level.

9. d Orbitals

10. f Orbitals

11. Electron Energy and Orbitals
In general, electrons in orbitals for higher levels have more energy.
Orbital energy by type: f > d > p > s
However, as the atom gets larger (# or electrons increases), there is some overlap between orbitals and principal energy levels.