Energy Levels
Ground State
Excited State
How is an electron cloud divided?
 The electron cloud is divided into 3 categories
 Energy levels (divisions of the electron cloud)


numbered consecutively from closest to farthest away from nucleus .
Electrons will occupy the location with the lowest amount of energy
 Sublevels (divisions of energy levels)
 designated by letters (s, p, d, f)
 number of sublevels in an energy level = # of the energy
 QW #1: how many energy levels are in E1? E2? E3?
 QW #2: Which sublevels are in E1?E2?E3?
 Start with s, then p, then d
 Orbitals (divisions of sublevels)
 number of orbitals in an energy level =
 “s” sublevel has 1 orbital
 “p” sublevel has 3 orbitals
 “d” sublevel has 5 orbitals
 “f” sublevel has 7 orbitals
Energy levels and sublevels
Energy Levels, Sublevels and Orbitals
•Each orbital has 2 electrons
•QW #3: HOW MANY ELECTRONS CAN EACH SUBLEVEL HOLD?
“s” = ___ e- “p” = ___ e- “d” = ___ e- “f” = ___ e•QW#4: HOW MANY ELECTRONS CAN EACH ENERGY LEVEL HOLD?
-the equation to figure that out is 2n2
- n = energy level
How do orbitals fill up?
 Electron orbitals fill up from lowest energy level to
highest, the idea is simple to follow as long as you
think of lower energy in terms of sublevel not energy
level
 For example: 4s orbital is lower in energy than 3d, so 4s
will fill up before 3d
 You can see the pattern in the diagram below:
Sublevel Periodic Table
Electron Configuration Notations
 Basic Electron Configuration
 Includes each sublevel

Example: Sulfur = 1s2, 2s2, 2p6, 3s2, 3p4
 Noble Gas Notation
 Shortcut of Basic electron configuration
 Only includes sublevels of the valence electrons

Example: Sulfur = [Ne]3s2, 3p4
 Orbital Diagram
 Just like Basic electron configuration but shows the
order that orbitals are filled
Valence Electrons
 HOEL (Highest Occupied Energy Level): energy level
furthest from the nucleus that contains at least one
electron
 How to determine this using electron configuration?
 Largest non-exponent number
 Example: Sulfur = 1s2, 2s2, 2p6, 3s2, 3p4
 The highest energy level is 3
 Valence Electrons: electrons in the HOEL
 How to determine this using electron configuration?

Add up exponents of terms in the HOEL
 Example: Sulfur = 1s2, 2s2, 2p6, 3s2, 3p4
 2+4 = 6 Therefore there are 6 valence electrons
Orbital Diagram
 Drawing of how electrons are arranged in orbitals;
 QW # 5:How many electrons are in an orbital?
 You only need to illustrate the HOEL
 Each line is an orbital
 All orbitals must have 1 electron within a sublevel before it can have double
occupancy
 This diagram illustrates spin of an electron
 If one electron is moving clockwise in an orbit, the other has to move
counterclockwise
Example: Sulfur