Atoms

Seite 1

- Describe the sub-particles of an atom and their physical properties as well as the term,

Energy Levels, Maximum number of electrons in each energy level.

Sub-particles : Electrons(-), Protons(+) & Neutrons(0)

Energy levels: Represents a permitted or allowed amount of energy.

Understanding Structure Of An Atom

Explain how Cr and Cu deviate from the Aufbau's Principle.

Deviation involve the placement of one or two ns electrons in an (n-1)d level and it occurs when a d level is almost full or half full.

- Cr produces a half-filled 3d subshell as an electron was transferred from the 4s to 3d subshell.

-Cu has a completely filled 3d subshell.

Electron configurations in which subshells are either half-filled or filled are rather stable.

Explain the arrangement of electrons in the respective energy levels and their sub-energy levels. (s,p,d,f sub-shells)

-s Orbitals : Consist of just one orbital

All s orbitals are spherical in shape.

-p Orbitals : Consist of 3 orbitals whose directions lie at 90' to one other along the axes of xyz.

Each p orbital is dumb-bell shaped.

-d Orbitals : Consist of 5 orbitals.

Apply Hund's Rule and Aufbau's Principle in the electronic configurations and orbital diagrams for elements.

-Hund's Rule: For orbitals of equal energy, there is one electron in each orbital before there is any pairing.

-Aufbau Principle : Electrons occupy orbitals of the lowest energy and fill each capacity before occupying higher energy orbitals.