4.1 Introduction to Chemical Bonding: The Octet Rule

all noble gas’ configs are ns²np⁶ valence shell arrangement (except He with 1s²)

Noble Gas Configuration

Formed when electrons are transferred from one atom to another

Ionic Bond

Positively charged ion formed when an atom loses electrons

Cation

Negatively charged ion formed when an atom gains electrons

Anion

The force that holds oppositely charged ions together in an ionic bond

Electrostatic Attraction

Formed when two atoms share one or more pairs of electrons

Covalent Bond

One shared pair of electrons

Single Bond

Two shared pairs of electrons

Double Bond

Three shared pairs of electrons

Triple Bond

Have low ionization energies (IE) and low electron affinities (EA)

Metals (Groups 1–2)

Have high IE and high EA

Nonmetals (Groups 14–17)

Occurs when s-block metals combine with p-block nonmetals (Groups 16 or 17)

Ionic Compound Formation

Occurs when p-block atoms bond with each other through covalent bonds

Molecular Compound Formation

Ionization Energy

energy required to remove an electron from one gaseous mole of an element

IE

Electron Affinity

energy released when one mol of a gaseous atom gains an electron

EA

Na (metal) + Cl (nonmetal) → NaCl

Example of Ionic Bond

H (nonmetal) + Cl (nonmetal) → HCl

Example of Covalent Bond

Explains atom stability through filled valence shells similar to noble gases

Octet Significance