Electron Location

Part 1 of 3

Scandium 3-D video (2:31)

Lec 5 | MIT 3.091 Introduction to Solid State Chemistry

quantum numbers start at 34 minutes

hydrogen

Animations of Electron Levels

Electron “jumping” website Electron levels animation link McGraw Hill animation link

normally electrons exist in the ground state, meaning they are as close to the nucleus as possible

when an electron is excited by adding energy to an atom, the electron will absorb energy and "jump" to a higher energy level heating a chemical with a Bunsen burner is enough energy to do this

Jumping Electrons

after a short time, this electron will spontaneously "fall" back to a lower energy level, giving off a quantum of light energy called a photon

the key to Bohr's theory was the fact that the electron could only "jump" and "fall" to precise energy levels, thus emitting a limited spectrum of light. quantum is the amount of energy required to

move an electron from one energy level to another

Quantum Numbers electrons display the properties of both waves and

particles. think of an atom as a very bizarre house (like an

inverted pyramid) with the nucleus living on the ground floor, and then various rooms (orbitals) on the higher floors occupied by the electrons

electrons fill low energy orbitals (closer to the nucleus) before they fill higher energy ones

electron configuration is defined to be the arrangement and distribution of electrons in atomic orbitals the electron configuration of each atom is made

up of four quantum numbers or letters, which describe different properties of each electron and its orbital.

think of the 4 quantum numbers as the address think of the 4 quantum numbers as the address of an electron… Country > State > City > Streetof an electron… Country > State > City > Street

Where is an electron? What level/size? What shape? Orientation (x, y, z axis)? Spin?

Quantum numbers give “the address” of the electron.

Principle quantum number (n) - describes the SIZE of the orbital or ENERGY LEVEL of the atom.

Angular quantum number (l) - describes the SHAPE of the orbital.

Magnetic quantum number (m) - describes an orbital's ORIENTATION in space. This tells the placement of the electrons in the sub-orbitals

Spin quantum number (s) - describes the SPIN or direction (clockwise or counter-clockwise) in which an electron spins.

QUANTUM NUMBERSQUANTUM NUMBERSQUANTUM NUMBERSQUANTUM NUMBERS

The The shape, size, and energyshape, size, and energy of each orbital is a of each orbital is a function of 3 quantum numbers which describe function of 3 quantum numbers which describe the location of an electron within an atom or ionthe location of an electron within an atom or ion

n n (principal)(principal) ---> energy level---> energy level

ll (orbital) (orbital) ---> shape of orbital---> shape of orbital

mmll (magnetic)(magnetic) ---> designates a particular ---> designates a particular suborbitalsuborbital

The fourth quantum number is not derived from the The fourth quantum number is not derived from the wave functionwave function

ss (spin)(spin) ---> spin of the electron ---> spin of the electron (clockwise or counterclockwise: ½ or – ½)(clockwise or counterclockwise: ½ or – ½)

Principle Quantum # (n)LEVEL/SIZE 1 2 3 4

Angular Quantum # (l)

ORBITAL SHAPE or

SUBLEVEL

s s p s p d s p d f

Magnetic Quantum #

(m)AXIS/

ORIENTATION

or ORBITALS

1

1 orbital

1 3

4 totalorbitals

1 3 5

9 total orbitals

1 3 5 7

16 total orbitals

Spin Quantum # (s)

DIRECTION OF

ELECTRON SPIN

2 e- 8 e- 18 e- 32 e-

Weird electron configuration video (3:24)