Quantum Mechanical Model & Orbitals

Development of Atomic Models These illustrations show how the atomic model has changed as scientists learned more about the atom’s structure.

Where are the electrons exactly? propeller has equal probability of being anywhere in the blurry region, but… …you cannot tell its exact location at any instant. (NOT THE BEST ANALOGY, BUT GOOD ENOUGH) The electron cloud of an atom is compared here to photographs of a spinning airplane propeller. a) The airplane propeller is somewhere in the blurry region it produces in this picture, but the picture does not tell you its exact position at any instant. b) Similarly, the electron cloud of an atom represents the locations where an electron is likely to be found.

Quantum Mechanical Model (Electron Cloud) (1926–Erwin Schrodinger & others) shows most probable locations of electrons equations describe electrons as waves in motion through space

Quantum Mechanical Model The electron is visualized not as a particle at some location in the atom, but its mass and charge are spread as a standing wave around the nucleus. energy levels 1,2,3,4 straightened out

Quantum Mechanical Model Bohr’s model shows electrons orbit the nucleus like planets going around the sun. de Broglie’s idea shows a wave along an orbit. Quantum Mechanical model: electrons are in a 3D “cloud” of orbits of wave equations (math) and probability.

energy levels have sublevels of different shapes (not perfect rings) 5.2 Atomic Orbitals Atomic Orbitals energy levels have sublevels of different shapes (not perfect rings like Bohr proposed)

energy levels have sublevels of different shapes (not perfect rings) 5.2 Atomic Orbitals Atomic Orbitals energy levels have sublevels of different shapes (not perfect rings like Bohr proposed)

2s 2p 1s 3s Electron energy levels have sublevels of different shapes orbital Nucleus 2p orbitals 1s orbital 3s orbital

3-D regions with a high probability of electrons atomic orbitals: s orbitals are spherical p orbitals are dumbbell-shaped in 3 directions d orbitals are clover-shaped in… there are 5 of them. *** DRAW ALL OF s p and d maybe even f f-orbitals are funky-shaped there are 7 of them.

Development of Atomic Models 1803 Dalton 1904 Thomson 1911 Rutherford 1913 Bohr These illustrations show how the atomic model has changed as scientists learned more about the atom’s structure. 1926 Quantum Mechanical Model

Quick Quiz! 1. What does the quantum mechanical model describe about atoms? the probable locations of electrons in atoms the precise locations of electrons in atoms the number of electrons in an atom how crazy chemistry is

Quick Quiz. 2. What do orbitals (s, p, d, f) tell us about the sublevel of an electron? the amount of energy in each electron the number of electrons in each sublevel the shape of the region they occupy that my brain feels mushy now