Chemistry Glossary

Allotropes … Different forms of the same element.

Atom … Basic unit of a chemical element.

Atomic Number … Number of protons in the nucleus of an atom, which determines the chemical properties of an element and its place in the periodic table.

Average Atomic Mass … Is the weighted average mass of its isotopes.

Binary Compound … Composed of two elements.

Boiling Point … The point in temperature when the liquid starts to boil.

Buoyancy … Ability of a fluid to exert an upward force on an object immersed in it.

Chemical Bond … Force that holds atoms together in a compound.

Chemical Change … A change of one substance to another.

Chemical Formula … A formula that shows what elements are in a compound and what it will become.

Chemical Property … Characteristic of a substance that indicates whether it can undergo a chemical change.

Chemical Reaction … More than one substances turning into other substances.

Coeffecients … Numbers in front of each substance in a equation.

Colloid … Type of mixture with particles that are larger than those in solutions, but not heavy enough to settle out.

Combustion Reaction … Substance reacts with oxygen to make heat and light.

Compound … A substance in which the atoms of 2 or more elements are combined.

Covalent Bond … Attraction formed when elements share electrons.

Decomposition Reaction … One substance breaks down, into 2 more.

Diatomic Molecule … Consists of 2 atoms of the same element in a covalent compound.

Diffusion … Spreading of particles throughout a given volume until they are distributed.

Distillation … A process for separating substances by evaporating a liquid and recondensing its vapor.

Double Displacement Reaction … Two elements replace another to make a product.

Ductile … Flexible.

Electron Cloud … Area around a nucleus where electrons are mostly found.

Electron Dot Diagram … Uses the symbol of the element and dots to represent electrons.

Electrons … Particles in a atom with a negative charge.

Element … If all the atoms in a substance has the same identity it becomes {blank}.

Groups … The vertical columns in the periodic table.

Heat of Fusion … The energy required to change a substance from a solid to a liquid at its melting point.

Heat of Vaporization … Amount of energy required for a liquid to become a gas.

Heterogeneous Mixture … Mixture in which different materials can easily be distinguished.

Homogeneous Mixture … Contains 2 or more gases, liquids, or solids substances blended evenly.

Ionic Bond … Force of attraction between opposite charges.

Isotopes … Atoms of the same element that have different numbers of neutrons.

Kinetic Theory … Explanation of how particles in matter behave.

Law of Conservation and Mass … The mass of all substances that are present before a chemical change equals the mass of all the substances after the change.

Malleable … Can be hammered.

Mass Number … This number is the sum of the number of protons and neutrons.

Melting Point … The point in temperature when the solid starts to liquefy.

Metallic Bonding … Positively charged metallic ions surrounded by a electron cloud.

Metalloids … Has properties of both nonmetals and metals.

Metals … Good conductors of heat and electricity.

Molecule … A neutral molecule that forms as a result of electron sharing.

Neutrons … Particles in a atom with no charge.

Nonmetals … Usually gasses or brittle solids at room temperature.

Nucleus … The center of a atom.

Oxidation Number … Tells you how many electrons an atom has gained or lost.

Pascal … Used to measure pressure.

Periodic Table … A table filled with elements in order of atomic numbers, etc.

Periods … Horizontal rows of elements.

Physical Change … A change in size, shape, or state.

Physical Property … Characteristic of a material you can observe without changing the identity.

Polyatomic Ion … Positively or negatively charged, covalently bonded group.

Pressure … Force exerted per area. (Formula)

Products … Substances that are made.

Protons … Particles in a atom with a positive charge.

Quarks … Smaller particles in neutrons and protons.

Reactants … Substances that react.

Semiconductors … Elements that conduct under circumstances.

Single Displacement Reaction … One element replaces another to make a product.

Solution … Homogeneous mixture with particles so small that they cannot be seen with a microscope.

Sublimation … The process of a solid going directly into a vapor.

Substance … A type of matter with a fixed composition.

Suspension … Heterogeneous mixture containing a liquid where visible particles settle.

Synthesis Reaction … 2 or more substances that combine to make another.

Transitional Elements … Between groups 1 and 2, and 13 and 18.

Tyndall Effect … Scattering of light by colloidal particles.

Viscosity … The resistance to flow by a fluid.