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Chemistry vocabulary words for students

Built for middle and high school students working through a chemistry unit, this list gathers the words that show up most in lessons on matter, atomic structure, and reactions. Use it to preview a chapter before class or to review key terms before a quiz.

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Chemistry vocabulary words for students

30 words
WordMeaningIn a sentenceSave
matternounAnything that has mass and takes up space.Air is matter even though we cannot usually see it.
atomnounThe smallest unit of an element that keeps that element's chemical identity.A water molecule contains two hydrogen atoms and one oxygen atom.
moleculenounThe smallest unit of a substance that still has all its chemical properties, made of two or more bonded atoms.A water molecule consists of two hydrogen atoms bonded to one oxygen atom.
elementnounA basic, essential part of something, or a pure chemical substance made of one type of atom.Trust is a crucial element of any successful long-term relationship.
compoundnounA substance formed when two or more chemical elements are combined in fixed proportions.Water is a compound made of two hydrogen atoms bonded to one oxygen atom.
mixturenounA substance made by combining two or more different materials that keep their own properties.The cake batter is a mixture of flour, eggs, sugar, and butter.
solutionnounA uniform mixture in which one or more substances are dissolved in another.Stirring the salt into water produced a clear solution.
solventnoun(Chemistry) A liquid substance capable of dissolving another substance to form a solution.The chemist used a solvent to remove the sticky residue from the glass beaker.
solutenounA substance that dissolves in a liquid to form a solution, as salt dissolves in water.In salt water, the salt is the solute and the water is the solvent.
massnounThe quantity of matter in an object, measured by its resistance to acceleration; also a large body or quantity of something.Scientists measured the mass of the asteroid using its gravitational pull.
volumenounThe degree of loudness of a sound, or the control that adjusts it.Please turn down the volume; the music is too loud for a library.
densitynounThe mass of a substance per unit of its volume, or, more generally, how tightly packed something is.Lead has a much higher density than aluminum, so it feels far heavier for its size.
protonnounA positively charged subatomic particle found in the nucleus of every atom.The number of protons in an atom determines which element it is.
neutronnounA subatomic particle with no electric charge, found in the nucleus of nearly every atom.Splitting an atom's nucleus releases neutrons along with a burst of energy.
electronnounA stable subatomic particle with a negative electric charge, found in every atom.Electrons orbit the nucleus of an atom in regions called electron clouds.
nucleusnounThe central part of an atom or cell that contains most of its mass or genetic material.The cell's nucleus holds the DNA that directs its growth and function.
isotopenounOne of two or more forms of a chemical element with the same protons but different numbers of neutrons.Carbon-14 is a radioactive isotope used to determine the age of ancient artifacts.
ionnounAn atom or molecule that has an electric charge because it has gained or lost electrons.Table salt dissolves in water into sodium and chloride ions.
reactionnounA response to something that has happened, been said, or been experienced.Her immediate reaction to the news was a mixture of shock and relief.
reactantnounA substance that takes part in and undergoes change during a chemical reaction.In this experiment, vinegar and baking soda are the two reactants that produce carbon dioxide.
productnounThe result of multiplying numbers or expressions.The product of 6 and 7 is 42.
catalystnounA substance that speeds up a chemical reaction without being consumed, or something that triggers significant change.The introduction of the new CEO acted as a catalyst for the company's turnaround.
bondnounA close connection or relationship linking two or more people, or a certificate representing a loan to be repaid with interest.The two sisters shared an unbreakable bond despite living on opposite coasts.
acidnounA chemical substance that reacts with a base to form a salt and typically tastes sour or is corrosive.Vinegar contains acetic acid, which gives it a sharp, sour taste.
basenounThe lowest part or foundation of something that supports it, or a place from which operations are organized.Workers poured concrete for the base of the new bridge before winter arrived.
valencenounThe combining power of an atom, determined by the number of electrons it can gain, lose, or share.Carbon has a valence of four, which lets it form stable bonds with many other atoms.
sublimationnounThe direct transformation of a substance from a solid into a gas without passing through a liquid state.Dry ice cools drinks through sublimation, turning straight into carbon dioxide gas.
evaporationnounThe change of a liquid into gas at the liquid's surface.Evaporation made the shallow puddle smaller during the afternoon.
condensationnounThe change of a gas into a liquid.Condensation formed droplets on the cold window.
periodic tablenounA chart that organizes all known chemical elements by increasing atomic number and shared properties.Chemistry students memorize the periodic table to understand how elements react with each other.

Reading the periodic table

The periodic table arranges elements by atomic number and groups them by shared properties. Rows are called periods and columns are called groups or families, and elements in the same group tend to react in similar ways. Knowing words like proton, electron, and valence helps explain why the table is organized the way it is, rather than just memorizing where each element sits.

Matter and its changes

Matter exists as a solid, liquid, gas, or plasma, and it can change from one state to another without becoming a new substance. Evaporation and condensation describe liquids turning to gas and back again, while sublimation is a solid turning directly into a gas. These words are useful for describing everyday changes as well as lab observations.

Frequently asked questions

What is the difference between mass and matter?

Matter is anything that takes up space and has mass; mass is the specific measurement of how much matter an object contains.

What are the states of matter?

The common states are solid, liquid, and gas, with plasma often added as a fourth state studied in more advanced chemistry.