Models of the Atom Mr. Smith's Chapter 5 (Bohr Model (Energy Levels…
Models of the Atom Mr. Smith's Chapter 5
Bohr Model (1913)
Electrons move in a circular obit at fixed distances from the nucleus.
Planetary Model (Planets traveling around the sun)
Dalton Model (1803)
Tiny, Indestructible Particles, with no internal structure. (tiny solid sphere)
Looks like a pool ball.
Thompson Model (1897)
"Plum Pudding Model"
Sphere with "bumps" of electrons (negatives)
Rutherford Model (1911)
Small, dense, positively charged nucleus. Electrons move around the nucleus.
Crazy Orbits around the nucleus.
Electron Cloud Model (1926)
Developed by mathematics to describe the motion of electrons.
Amount of energy needed to move an electron from one level to another.
Quantum Mechanical Model
determines the allowed energies an electron can have and how likely it is to find the electron in carious locations around the nucleus.
sublevels = 2
2s (one orbital), 2p (3 orbitals)
3s (1 orbital), 3p (3 orbitals), 3d (5 orbitals)
sublevels = 1
1s (1 orbital)
4s (1 orbital), 4p (3 orbitals), 4d (5 orbitals), 4f (7 orbitals)
s orbitals look like spheres
p orbitals look like dumbells, or figure 8
The Guiding Principles:
Pauli Exclusion Principle
Each orbital will have two electrons
They spin in opposite directions.
Electrons will fill one spot in each orbital first, then fill the second.
Electrons will occupy the lowest energy levels first!
Some electron configurations differ from those assigned using the aufbau principle because half-filled sublevels are not as stable as filled sublevels, but they are more stable than other configurations.