High School Chemistry Unit 3 Study Guide

Octet Rule
Elements will gain or lose electrons to a stable outer 8 in s,p orbitals

Valence Electrons
Electrons in outermost energy level

Ion
atoms or molecules that have positive or negative charge

Cation
ion w/ positive charge

Anion
ion w/ negative charge

Salt
ionic compound other than H+ as cation or OH- as anion

Lattice Energy
energy released when ionic bonds are formed

Crystal Lattice
Regular 3D arrangement of atoms/ions in a crystal

Unit Cell
smallest portion of a crystal lattice; shows 3D shape of entire lattice

Polyatomic Ion
ion made of two or more atoms

Stability
filled energy levels and subshells make an atom stable (noble gases)

Energy Transfer

Ionic Bond
bond formed by attraction of opposite charged ions

Ionic Compound
Compound formed by cation and anion; W/ combined charge of 0

Monoatomic Ion
anion or cation formed by single atom

Binary Compound
Composed of two elements

Percent Composition
total mass contributed by an element in a compound

Empirical Formula
Simplest formula of elements combined; Shows atomic ratios

Molecular Formula
How compound actually exists

IUPAC
International Union of Pure and Applied Chemistry

Pure Science
sake of science

Applied Science
toward a specific goal or outcome

Formula Unit
represents an amount of a compound or number of molecules

Atomic Mass Scale
Scale for masses of atoms

amu
atomic mass unit

Molecular Mass
total mass of a moelcule

Formula Mass
total mass of sample

Chemical Reaction
Process by whichc one or more substances are changed into one or more different substances

Reactants
substances at beginning of reaction

Products
substances at the end of reaction

Chemical Equation
shows relationship between reactants and products

Coefficient
number in front of compound or element, can be changed in an equation

Combustion Reaction
hydrocarbon + O₂ → CO₂ + H₂O

Synthesis Reaction
X + Y + Z → XYZ
building from simple to complex

Decomposition Reaction
XYZ → XY + Z
going from complex to simple

Double Displacement Reaction
ionic components switch partners in a reaction

Spectator Ions
ions not involved in a reaction

Single Displacement Reaction
an element replaces it’s like charged ion in a compound

Law of Conservation of Matter
matter can not be created or destroyed, it can only change form