Chapter 3 — Bonding, Ions, and Compounds

Atom or molecule carrying a net charge

Ion

Positive ion

Cation

Negative ion

Anion

Cation formation

Loss of electrons

Anion formation

Gain of electrons

Several covalently bonded atoms with one charge

Polyatomic ion

How do cations and anions differ?

Cations lose electrons and become positive; anions gain electrons and become negative.

Positive polyatomic ion

Ammonium

Ammonium formula

NH₄⁺

Phosphate formula

PO₄³⁻

Hydrogen phosphate formula

HPO₄²⁻

Dihydrogen phosphate formula

H₂PO₄⁻

Carbonate formula

CO₃²⁻

Bicarbonate formula

HCO₃⁻

How does adding H⁺ affect a polyatomic ion’s charge?

It makes the charge one unit less negative.

Oxoanion with more oxygen

-ate

Oxoanion with less oxygen

-ite

Nitrate formula

NO₃⁻

Nitrite formula

NO₂⁻

Sulfate formula

SO₄²⁻

Sulfite formula

SO₃²⁻

How do nitrate and nitrite differ?

Nitrate has one more oxygen.

How do sulfate and sulfite differ?

Sulfate has one more oxygen.

Hypochlorite formula

ClO⁻

Chlorite formula

ClO₂⁻

Chlorate formula

ClO₃⁻

Perchlorate formula

ClO₄⁻

Chlorine oxoanion oxygen order

Hypochlorite < chlorite < chlorate < perchlorate

Permanganate formula

MnO₄⁻

Chromate formula

CrO₄²⁻

Cyanide formula

CN⁻

Polyatomic ion without oxygen

Cyanide

Compound containing two different elements

Binary compound

Typical ionic-compound elements

Metal and nonmetal

Ionic-compound naming order

Cation first, anion second

Ending for monatomic anion

-ide

NaCl name

Sodium chloride

CaF₂ name

Calcium fluoride

Are prefixes used for ionic compounds?

No

Why is CaF₂ not calcium difluoride?

Ionic compounds do not use numerical prefixes.

Purpose of a Roman numeral

Shows a metal’s oxidation state

Fe₂O₃ name

Iron(III) oxide

Iron charge in Fe₂O₃

+3

Why is Fe₂O₃ iron(III) oxide?

Three O²⁻ ions total −6, so each iron must be +3.

Typical molecular-compound elements

Two nonmetals

Molecular-compound bonding

Electron sharing

Prefix for 1

Mono-

Prefix for 2

Di-

Prefix for 3

Tri-

Prefix for 4

Tetra-

Prefix for 5

Penta-

Prefix for 6

Hexa-

Prefix for 7

Hepta-

Prefix for 8

Octa-

Prefix for 9

Nona-

Prefix for 10

Deca-

CO name

Carbon monoxide

CO₂ name

Carbon dioxide

When is mono- generally omitted?

On the first element

How do ionic and molecular naming differ?

Ionic compounds avoid prefixes; molecular compounds use prefixes.

Forces holding atoms together inside a compound

Intramolecular forces

Forces acting between separate molecules

Intermolecular forces

Meaning of intra

Within

Meaning of inter

Between

How do intramolecular and intermolecular forces differ?

Intramolecular forces bond atoms; intermolecular forces attract separate molecules.

Stable outer-shell target for many atoms

8 electrons

Group naturally having full valence shells

Noble gases

Why do atoms bond?

To reach a more stable valence-shell arrangement.

Bond formed by electron sharing

Covalent bond

Atoms commonly forming covalent bonds

Nonmetals

Equal electron sharing

Nonpolar covalent bond

Unequal electron sharing

Polar covalent bond

Electronegativity difference under 0.5

Nonpolar covalent

Electronegativity difference from 0.5 to 2.0

Polar covalent

Electronegativity difference above 2.0

Ionic

How do nonpolar and polar covalent bonds differ?

Nonpolar bonds share equally; polar bonds share unequally.

Example of a nonpolar bond

C–C

Example of a polar bond

H–Cl

Partially positive symbol

δ⁺

Partially negative symbol

δ⁻

Partial charge on H in H–Cl

δ⁺

Partial charge on Cl in H–Cl

δ⁻

Why is H–Cl polar?

Chlorine attracts the bonding electrons more strongly.

Bond where one atom supplies both electrons

Coordinate covalent bond

Another name for coordinate covalent bond

Dative bond

Common coordinate-bond setting

Metal-ligand complexes

Biological coordinate-bond example

Heme iron bonded to nitrogen

How does a coordinate bond differ from a regular covalent bond?

Both electrons originally come from one atom.

Bond formed by electron transfer

Ionic bond

Typical ionic-bond elements

Metal and nonmetal

Force holding ions together

Electrostatic attraction

Ions present in MgCl₂

Mg²⁺ and two Cl⁻

How do ionic and covalent bonds differ?

Ionic bonds transfer electrons; covalent bonds share electrons.

Bonding among metal atoms

Metallic bonding

Metallic-electron model

Sea of electrons

Electrons in metallic bonds

Delocalized electrons

Metal property caused by mobile electrons

Electrical conductivity

Ability of a metal to be shaped

Malleability

Why do metals conduct electricity?

Their delocalized electrons can move.

Why are metals malleable?

Metal atoms can shift while the electron sea continues holding them together.