[عاطف خليفة]

SUMMARY

Quantum

It is the amount of energy absorbed or emitted when an electron jumps from one energy level to another

The Dual nature of the electron

It means that the electron is a particle and it has wave properties

Uncertainty Principle (Probability)

- It is impossible to determine both the location and the velocity, of the electron precisely at the same time

- It is probable to locate the electron in this or that place

The Electron Cloud (Orbital)

It is the region of space around the nucleus where is a great probability of finding the electron.

Quantum Numbers

They define the energy, shape and direction of orbitals

The principle quantum number

It defines the principle energy level and the number of electrons which can occupy a given principal energy level

The subsidiary quantum number (Orbital or ozimuthal)

- It defines the energy sublevels
- The number of sublevels equals the number of the principal level to which these sublevels belong

The magnetic quantum number
It defines the orbitals of a given energy sublevel and their directions .

The spin quantum number

It describes the spin motion of an electron around its own axis
clockwise or anti-clockwise).

The auf-bau principle

Electrons occupy the orbitals in the order of increasing orbital energy. the lowest energy orbitals are filled first.

Hund’s rule
No electron pairing takes place in a given sublevel until each orbital contains one electron