Ch 2 Narration 2(2.3&2.4)

Molecule

Two or more atoms of the same element combined chemically.

Compound

Two or more atoms of different elements combined chemically to form a molecule.

Electron Shells

Energy levels around an atom where electrons are located.

Valence Shell

The outermost electron shell of an atom that determines its chemical reactivity.

Rule of Eights

Atoms are stable when their valence shell has 8 electrons.

Ionic Bond

A chemical bond formed when electrons are completely transferred from one atom to another.

Cation

A positively charged ion, created when an atom loses electrons.

Anion

A negatively charged ion, created when an atom gains electrons.

Covalent Bond

A chemical bond formed when atoms share electrons.

Polar Covalent Bond

A bond where electrons are not shared equally, resulting in a molecule with a positive and negative side.

Nonpolar Covalent Bond

A bond where electrons are shared equally between atoms.

Hydrogen Bond

A weak bond formed between water molecules, important for many of water's characteristics.

Synthesis Reaction

A reaction where smaller particles bond to form larger, more complex molecules.

Decomposition Reaction

A reaction where bonds are broken in larger molecules to produce smaller ones.

Exchange Reaction

A chemical reaction where bonds are both made and broken, resulting in new molecules.