Key Concepts on Matter and Atomic Structure

Flashcards summarizing important vocabulary related to matter, elements, compounds, and atomic structure.

Matter

Anything that occupies space and has mass.

Mass

The amount of matter contained in an object, same regardless of location.

Weight

The mass of an object as affected by the pull of gravity.

Element

A pure substance that cannot be created or broken down by ordinary chemical means.

Compound

A substance composed of two or more elements joined by chemical bonds.

Atom

The smallest quantity of an element that retains the unique properties of that element.

Subatomic Particles

Particles smaller than atoms; primarily protons, neutrons, and electrons.

Proton

A positively charged particle found in the nucleus of an atom.

Neutron

A non-charged particle found in the nucleus of an atom.

Electron

A negatively charged particle that orbits the nucleus of an atom.

Atomic Number

The number of protons in the nucleus of an atom, which defines the element.

Mass Number

The sum of the number of protons and neutrons in the nucleus of an atom.

Isotope

Different forms of an element that have the same number of protons but different numbers of neutrons.

Valence Shell

The outermost shell of electrons in an atom that determines its reactivity.

Octet Rule

Atoms tend to react in a way that results in eight electrons in their valence shell.