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
“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
 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
 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
 This diagram illustrates spin of an electron
 If one electron is moving clockwise in an orbit, the other has to move
Example: Sulfur

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