Chemistry Semester 1 Final Study Guide

Proton

Subatomic particle with a positive charge

Neutron

Subatomic particle with no charge

Electron

Subatomic particle with a negative charge

Atomic number

Number of protons in an atom

Mass number

Sum of protons + neutrons

Isotopes

Atoms of the same element with different numbers of neutrons

Atomic weight

Average mass of an element's atoms (accounts for isotopes)

Ion

Atom with a positive or negative charge

Polyatomic ion

Ion made of multiple atoms with a charge

Cation

Positive ion (loses electrons)

Anion

Negative ion (gains electrons)

Covalent bond

Atoms share electrons

Ionic bond

Electrons are transferred from one atom to another

Polar covalent bond

Electrons shared unequally; molecule has partial charges

Nonpolar covalent bond

Electrons shared equally; molecule has no charge separation

Octet rule

Atoms are most stable with 8 electrons in their outer shell

Single bond

One pair of shared electrons

Double bond

Two pairs of shared electrons

Triple bond

Three pairs of shared electrons

Element

Pure substance made of one type of atom

Compound

Substance made of two or more elements chemically combined

Mixture

Two or more substances physically combined

Hydrate

Compound that contains water molecules

Anhydrate

Compound without water molecules

Precipitation

Formation of a solid from a solution

Energy

Ability to do work or cause change

Endothermic

Absorbs heat

Exothermic

Releases heat

Ionization

Process of forming ions

Electronegativity

Atom's ability to attract electrons

Atomic radius

Distance from the nucleus to the outermost electron

Period / series

Horizontal row of elements; properties change across

Group / family

Vertical column of elements; similar properties

Metal

Shiny, conducts electricity, usually loses electrons

Nonmetal

Dull, poor conductor, usually gains electrons

Metalloid

Has properties of both metals and nonmetals

Alkali metals (Group 1)

Very reactive metals

Alkaline earth metals (Group 2)

Reactive metals

Halogens (Group 17)

Very reactive nonmetals

Noble gases (Group 18)

Inert, full outer shell

Transition elements (Groups 3-12)

Metals with variable charges

Most active metal

Francium (Fr), Group 1

Most active nonmetal

Fluorine (F), Group 17

Mole / Avogadro's number

1 mole = 6.022×10²³ particles

Gram

Unit of mass

Chemical

Substance with a defined composition

Types of crystals

Ionic, covalent, metallic, molecular

Metallic network

Metals bonded in a lattice; electrons move freely

Ionic molecular

Combination of ionic and molecular bonding