Atomic Structure
Miha LeeCalifornia State University,
Northridge
List of Content1. Particles in a Atom
• Nucelus => Neutrons & Protons• Electrons
2. Atomic Structure• Bohr => energy level of electron shell• Shrodinger => orbitals & electron cloud
3. Electron Configuration• Rule of Elctronic Configuration • Atoms’ Electronic Configuration• Links for Self-study
ElectronJ.J. Thomson Cathode-ray
The atom has a lot of tiny, negatively charged particles named elec-trons stuck in it.
Nucelus 1Rutherford α particle scatter-
ing
Nucelus 2The atom has a
small, dense, posi-tively charged nu-cleus and electrons at a distance.
The vast majority of the volume of the atom is empty space.
Particles in NucleusProton
1.602×10−19 C1.673×10−27 kg
Neutronno net charge1.675×10−27 kg
Atomic Structure
Bohr => elenergy level of electron shells
Schrodinger => orbitals & electron cloud
Bohr’s Atomic Model 1Cause: Line spectrum of atoms =>
discrete energy levels in an atom
Bohr’s Atomic Model 2Borh’s idea about
Line spectrum Electrons orbit
around the nucleus in discret allowed energy levels (electron shells).
Electrons gain and lose energy by jumping from one orbit to another.
Atomic Orbitals 1Schrodinger
Electrons’ motion is described as wave-function.
Probaility of finding electrons is caculated from wave function and named orbital.
Atomic Orbitals 2Watch wave functi
ons and orbitalsElctron cloud:
probaility of find-ing electron (or-bital) decribed with dots
Atomoic Orbitals 3Orbitals: area of 90~95% of
probaility to find electronss orbitalp orbials
d orbitals
Electronic Configuration 1Each orbital can only
contain a maxi-mum of 2 electrons.
Elctron shells at a higher energy level have more orbitals.
Order of filling energy levels => 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6
Rule of Elctronic Configura-tion
The Aufbau Principle The electrons occupy the lowest energy orbitals
available. The “Ground State” for an atom is when every electron is in its lowest energy orbital.
The Pauli Exclusion Principle Each orbital can be occupied by no more than two
electrons.Hund’s Rule
When more than one orbital exists of the same en-ergy (p, d, and f orbitals), place one electron in each orbital
Atoms’ Electronic Configura-tion
Links for Electronic Configura-tion
Electronic Structures Electron Configuration Atomic electron configurations
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