Matter, Elements and Atomic Structure - Vocabulary Flashcards

A set of vocabulary flashcards covering matter classification, elements, and basic atomic structure.

Matter

Anything that occupies space and has mass.

Pure substance

A material made of only one kind of molecule.

Mixture

A combination of two or more substances that are not chemically bonded.

Molecule

The smallest particle of a substance that retains its chemical properties; composed of one or more atoms.

Element

A pure substance that cannot be broken down into simpler substances by physical or chemical means and is made of only one kind of atom.

Atomic number

The number of protons in the nucleus of an atom, unique to each element.

Natural element

One of the 92 elements that occur in nature.

Artificial element

One of the 26 elements synthesized by humans; all are heavier than uranium.

Hydrogen

The lightest known element.

Uranium

The heaviest naturally occurring element.

Metals

Elements that typically are solid, shiny, conduct heat and electricity, and are malleable (e.g., iron, copper, gold).

Non-metals

Elements that generally lack metallic properties; many are gases or brittle solids (e.g., oxygen, nitrogen).

Metalloids

Elements with properties intermediate between metals and non-metals.

Inert gases

Also called noble gases; elements that are largely unreactive due to a full outer electron shell.

Atom

The smallest particle of an element that can take part in a chemical reaction and retains the element’s identity.

Sub-atomic particle

Particles that make up atoms: electrons, protons, and neutrons.

Electron

A negatively charged sub-atomic particle that orbits the atomic nucleus.

Proton

A positively charged sub-atomic particle located in the nucleus.

Neutron

An electrically neutral sub-atomic particle found in the nucleus.

Nucleus

The central, positively charged core of an atom containing protons and neutrons.

Orbit (shell/energy level)

A fixed circular path around the nucleus where an electron revolves, associated with a specific energy.

Electrically neutral atom

An atom in which the number of electrons equals the number of protons.