Atomic Structure and Electron Structure

Relative Atomic Mass

Average mass of one atom of an element compared with 1/12th mass of an atom of carbon-12

Calculating R.A.M

An Atomic Orbital

A region within an atom that can hold up to 2 electrons with opposite spins

S and P Orbitals

• S orbital - Spherical

• P orbital - Dumbell shape

Electron Configurations

1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²

Noble Gas configuration

A short hand electron configuration can be written using the electronic configuration of noble gases e.g.

• Ni: [Ar] 4s²3d⁸

Configuration exceptions and reasons

• Chromium - 1s²2s²2p⁶3s²3p⁶4s¹3d⁵

• Copper - 1s²2s²2p⁶3s²3p⁶4s¹3d¹⁰

  Reason: They represent more stable arrangements