Covalent Compounds and Ionic/Covalent/Metallic Bonds

Ionic compound

Metal + nonmetal (M + nM)

Covalent compound

Nonmetal + nonmetal (nM + nM)

Metallic bonding

Metal + metal (M + M)

Ionic bonding

One atom transfers electrons to another atom, creating positive and negative ions.

Ionic crystal lattice

A repeating, organized arrangement of positive and negative ions.

Ionic particles

Can be colorless or very colorful.

Ionic properties

Hard and brittle; generally high melting and boiling points.

Ionic conductivity

Conducts electricity when melted (molten) OR dissolved in water.

Ionic solubility

Many ionic compounds dissolve in water.

Ionic examples

Na₂CO₃ and NaHCO₃

Covalent molecules

Covalent substances form individual molecules.

Covalent bonding

Atoms share electrons.

Covalent molecular structure

Molecules can have different shapes depending on how their atoms are arranged.

Covalent properties

Usually low melting and boiling points; generally poor conductors of electricity.

Covalent examples

H₂O, NH₃, C₆H₁₂O₆, and acetone (CH₃)₂CO

Metallic bonding model

Metal atoms are arranged in a lattice surrounded by freely moving/delocalized electrons.

Metallic properties

Shiny, malleable, and good conductors of electricity.

Malleable

Can be hammered or shaped without breaking.

Metallic lattice

Metal atoms form a packed, repeating structure.

Metallic conductivity

Metals conduct electricity because their electrons can move freely.

Metallic examples

Brass, bronze, dental amalgam, stainless steel, and 14k gold.

Ionic electron movement

An atom loses electron(s) while another atom gains electron(s).

Covalent electron movement

Atoms share electrons rather than transferring them completely.

Metallic electron movement

Valence electrons are shared throughout the metal rather than belonging to one specific atom.

Ion

An atom or group of atoms with a positive or negative charge caused by gaining or losing electrons.

Cation

A positively charged ion formed when an atom loses electrons.

Anion

A negatively charged ion formed when an atom gains electrons.

Ionic bond

The attraction between oppositely charged ions.

Why ionic compounds conduct when dissolved

Their ions are free to move through the solution.

Why solid ionic compounds do not conduct well

The ions are locked into place in the crystal lattice.

Why metals conduct electricity

Their electrons can move freely through the metal.Covalent compound

CO

Carbon monoxide

CO₂

Carbon dioxide

PCl₅

Phosphorus pentachloride

S₂O₄

Disulfur tetroxide

H₂O

Water

NH₃

Ammonia

1

mono-

2

di-

3

tri-

4

tetra-

5

penta-

6

hexa-

7

hepta-

8

octa-

9

nona-

10

deca-

First element in a covalent compound

Use a prefix to show how many atoms there are, but usually don't use mono- for the first element

Second element in a covalent compound

Always use a prefix to show the number of atoms and change the ending to -ide

1 atom prefix

mono-

2 atoms prefix

di-

3 atoms prefix

tri-

4 atoms prefix

tetra-

5 atoms prefix

penta-

6 atoms prefix

hexa-

7 atoms prefix

hepta-

8 atoms prefix

octa-

9 atoms prefix

nona-

10 atoms prefix

deca-

CO₁

Carbon monoxide

CO₂

Carbon dioxide

PCl₅

Phosphorus pentachloride

S₂O₄

Disulfur tetroxide

Special names to remember

H₂O = water; NH₃ = ammonia