Atom
The smallest unit of an element that still keeps that element's properties.
Public flashcard set
Chemistry Basics
Core chemistry terms for fast review and active recall.
chemistry science basics
Flashcards
Element
A pure substance made of only one kind of atom.
Compound
A substance made from two or more different elements chemically bonded.
Mixture
A physical combination of substances that are not chemically bonded.
Molecule
Two or more atoms held together by chemical bonds.
Ion
An atom or molecule with a net electric charge.
Proton
A positively charged particle in the nucleus.
Neutron
A neutral particle in the nucleus.
Electron
A negatively charged particle found outside the nucleus.
Chemical bond
The force that holds atoms together in a compound or molecule.
Periodic table
A chart that organizes all known elements by atomic number and repeating properties.
Atomic number
The number of protons in the nucleus of an atom.
Mass number
The total number of protons and neutrons in the nucleus.
Isotope
Atoms of the same element with different numbers of neutrons.
Valence shell
The outermost energy level of an atom.
Valence electrons
Electrons in the outermost energy level.
Chemical formula
A shorthand that shows which elements are present and how many of each.
Subscript
A small number written after a symbol that shows how many of that particle are present.
Coefficient
A number placed in front of a formula to show how many units are involved.
Conservation of mass
Matter is not created or destroyed in a chemical reaction.
Matter
Anything that has mass and takes up space.
Physical property
A characteristic you can observe without changing what a substance is.
Chemical property
A characteristic that describes how a substance can change into a new substance.
Physical change
A change in form or state without making a new substance.
Chemical change
A change that produces one or more new substances.
Reactant
A starting substance in a chemical reaction.
Product
A substance formed in a chemical reaction.
Acid
A substance that releases hydrogen ions in water.
Base
A substance that accepts hydrogen ions or releases hydroxide ions in water.
pH
A scale that shows how acidic or basic a solution is.
Density
Mass per unit volume.
Volume
The amount of space an object or substance occupies.
Mass
The amount of matter in an object.
Temperature
A measure of the average kinetic energy of particles.
Solute
The substance that gets dissolved.
Solvent
The substance that does the dissolving.
Solution
A homogeneous mixture with evenly distributed particles.
Suspension
A mixture with particles that settle out over time.
Filtration
A separation method that uses a barrier to trap solid particles.
Evaporation
The change from liquid to gas at the surface.
Mole
A counting unit used to measure huge numbers of particles.
Avogadro's number
6.02 × 10^23 particles in one mole.
Molar mass
The mass of one mole of a substance.
Empirical formula
The simplest whole-number ratio of particles in a substance.
Molecular formula
The actual number of each kind of particle in one unit of a substance.
Chemical equation
A symbolic way to show a reaction using formulas and symbols.
Catalyst
A substance that speeds up a reaction without being used up.
Activation energy
The minimum energy needed for a reaction to start.
Endothermic
A process that absorbs energy from its surroundings.
Exothermic
A process that releases energy to its surroundings.