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27 terms

Unit 1 Nature of Matter

atoms, elements, molecules, compounds, and mixtures, states of matter, physical and chemical changes
STUDY
PLAY
ATOM
smallest particle of an element
ELEMENT
a pure substance made of only one kind of atom
NUCLEUS
the positively charged dense center of an atom
PROTON
a subatomic particle that has a positive charge and that is found in the nucleus of an atom
NEUTRON
a subatomic particle that has no charge and that is found in the nucleus of an atom
ELECTRON
negatively charged particle; located outside the atomic nucleus
ATOMIC NUMBER
the number of protons in the nucleus of an atom
NEUTRAL
having no net electric charge
ATOMIC MASS
Total mass of the protons and neutrons in an atom, measured in atomic mass units
CHEMICAL SYMBOL
a one- or two- letter representation of an element
PURE SUBSTANCE
matter that always has exactly the same composition. Homogeneous
COMPOUND
a substance made up of atoms of two or more different elements joined by chemical bonds
MOLECULE
the smallest particle (one or more atoms) of a substance that has all the properties of that substance
CHEMICAL FORMULA
a combination of chemical symbols and numbers to represent a substance
SUBSCRIPT
a number in a chemical formula that tells the number of atoms in a molecule or the ratio of elements in a compound
MIXTURE
A combination of two or more substances that are not chemically combined
STATE OF MATTER
a physical property that describes matter as a solid, liquid, or gas
SOLID
a form of matter that has a definite shape and volume
LIQUID
A state of matter that has no definite shape but has a definite volume
GAS
A state of matter with no definite shape or volume
MELTING POINT
the temperature at which a solid becomes a liquid
VAPORIZATION
the process by which a liquid or solid changes to a gas
BOILING POINT
the temperature at which a substance changes from a liquid to a gas
CONDENSATION
the process of changing from a gaseous to a liquid or solid state
FREEZING POINT
the temperature at which a substance changes from a liquid to a solid. The freezing point and melting point are EXACTLY the same!
SUBLIMATION
a change directly from the solid to the gaseous state without becoming liquid
PLASMA
a state of matter that starts as a gas and then becomes ionized