Chem chapters 4-6

Atom

Smallest unit of an element that retains its identity

Proton

Positively charged particle in the nucleus

Neutron

Neutral particle in the nucleus

Electron

Negatively charged particle outside the nucleus

Atomic Number

Number of protons in an atom

Mass Number

Number of protons plus neutrons

Isotope

Atoms of the same element with different numbers of neutrons

Ion

Atom with a charge due to gain or loss of electrons

Cation

Positively charged ion

Anion

Negatively charged ion

Periodic Table

Arrangement of elements by atomic number

Group

Vertical column on the periodic table

Period

Horizontal row on the periodic table

Atomic Mass

Weighted average mass of an element's isotopes

Compound

Two or more elements chemically combined

Ionic Compound

Compound formed from cations and anions

Molecular Compound

Compound formed by sharing electrons

Formula Unit

Lowest whole-number ratio in an ionic compound

Polyatomic Ion

Group of atoms with an overall charge

Nitrate

NO3-

Nitrite

NO2-

Hydroxide

OH-

Carbonate

CO3^2-

Sulfate

SO4^2-

Phosphate

PO4^3-

Chemical Formula

Representation of a compound using symbols and subscripts

Formula Mass

Sum of atomic masses in a compound

Roman Numeral System

Used to show metal ion charge in compound names

Prefix

Indicates number of atoms in molecular compounds

Mono

One

Di

Two

Tri

Three

Tetra

Four

Penta

Five

Hexa

Six

Hepta

Seven

Octa

Eight

Nona

Nine

Deca

Ten

Binary Acid

Acid containing hydrogen and one nonmetal

Oxyacid

Acid containing oxygen

Mole

6.022 × 10^23 particles

Avogadro's Number

6.022 × 10^23 particles per mole

Molar Mass

Mass of one mole of a substance

Percent Composition

Percent by mass of each element in a compound

Empirical Formula

Simplest whole-number ratio of atoms

Molecular Formula

Actual number of atoms in a molecule

Gram-to-Mole Conversion

Divide by molar mass

Mole-to-Gram Conversion

Multiply by molar mass

Mole-to-Particle Conversion

Multiply by 6.022 × 10^23

Particle-to-Mole Conversion

Divide by 6.022 × 10^23