atomic structure. electron configurations the way electrons are arranged around the nucleus
TRANSCRIPT
Atomic Structure
Electron Configurations
• The way electrons are arranged around the nucleus
Standard Notation of Fluorine
Main Energy
Level
Numbers
1, 2, 2Sublevels
Number of electrons in the sub level 2,2,5
1s2 2s2 2p5
Electron Configuration • Energy level of an electron is the region around the
nucleus where it is likely to be moving– N = 1, 2, 3 ,4
• Within each energy level are sub-levels– s, p, d and f
• Each sub-level corresponds to a different cloud shape or atomic orbital
• Atomic orbital is a region where there is a high probability of finding an electron
• Each type of orbital has a unique shape:– s orbitals have a spherical shape (1 orbital)– p orbitals have a dumbbell shape (3 orbitals)– d and f orbitals have more complex shapes (5 orbitals, 7 orbitals)
Electron Configurations
• Lowest energy level (n=1) has only 1 sub-level:– 1s
• Second energy level (n=2) has 2 sub-levels:– 2s and 2p
• Third energy level (n=3) has 3 sublevels:– 3s, 3p and 3d
• Fourth energy level (n=4) has 4 sub-levels:– 4s, 4p, 4d and 4f
Electron Configurations
• How electrons fill the orbitals is based on 3 rules:– The Aufbau principle– The Pauli Exclusion principle– Hund’s rule
Orbital Diagram
Electron Configurations
• The Pauli exclusion principle– Atomic orbital may describe at most 2 electrons
– Electrons must have opposite spins– ↑↓
Electron Configurations
• Hund’s rule• In a set of orbitals, the electrons will fill the
orbitals in a way that would give the maximum number of parallel spins (maximum number of unpaired electrons)
• ↑ ↑ ↑
• Analogy: Students could fill each seat of a school bus, one person at a time, before doubling up.
Orbital Diagram for Hydrogen
1s1
OrbitalDiagram for
Helium1s2
Orbital Diagram for
Lithium1s22s1
Orbital Diagram for
Beryllium1s22s2
Orbital Diagram for
Boron1s22s22p1
OrbitalDiagram for
Carbon1s22s22p2
Orbital Diagram for
Nitrogen1s22s22p3
Standard Notation of Fluorine
Main Energy
Level
Numbers
1, 2, 2Sublevels
Number of electrons in the sub level 2,2,5
1s2 2s2 2p5
Electron Configurations
Electron Configurations
Electron Configurations
• What is the electron configuration for?– Hydrogen
– Lithium
– Fluorine
Electron Configurations – Sodium
– Sulphur
– Rubidium
– Complete the following worksheets – Electron Configurations Level 1– Electron Configurations Level 2– Electron Configurations Worksheet 4