Electron Orbitals

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 Add up exponents of terms in the HOEL 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