Science Structure and Properties of Matter Review

element

element

a pure substance that cannot be broken down into simpler substances by chemical or physical means

compound

a pure substance made of two or more elements chemically combined

chemical formula

a combination of chemical symbols and numbers to represent a substance

atomic number

the number of protons in the nucleus of an atom

mass number

the number of protons plus neutrons in the nucleus

atomic mass

the average mass of all the isotopes of an element

protons

positively charged particles found in the nucleus of an atom

neutrons

the particles of the nucleus that have no charge

electrons

negatively charged subatomic particles

chemical symbol

one or two letters that represents an element

atomic theory

a theory that states that all matter is composed of tiny particles called atoms.

atom

a basic particle from which all elements are made; basic building block of matter

molecule

a group of two or more atoms chemically bonded together

Periodic Table of Elements

a classification system in which all known elements are arranged

nucleus

center of an atom containing most of its mass and a positive charge

electron cloud

a region of overlapping orbitals around the nucleus of an atom where electrons are likely to be found

matter

anything that has mass and takes up space (volume)

pure substance

a single kind of matter that is pure and has a specific set of properties.

properties

characteristics or qualities used to describe an object

subatomic particles

smaller particles that make up an atom (protons, neutrons, & electrons)

mixture

A combination of two or more substances that are not chemically combined

synthetic material

Material that is not found in nature, such as glass, concrete, and plastic.

ion

An atom or group of atoms that has a positive or negative charge.

isotope

Atoms of the same element that have different numbers of neutrons

extended structure

a structure whose subunits occur in a constant ratio and are arranged in a repeating pattern; the subunit can be individual atoms or a molecule

pH

hydrogen ion concentration (potential hydrogen); how acidic or basic a substance is