Fundamentals of Chemistry (2.2) Terms

Matter

Anything that has mass and occupies space.

Mass

The amount of matter present in a substance or object.

Weight

A measure of how the force of gravity acts on an object.

Chemistry

The science of the composition and interactions of matter.

Biochemistry:

A field of life science (biological chemistry) that explains physiological processes and helps detect, diagnose, and treat disease.

Element

Any of the fundamental chemicals substances, each characterized by a distinct type of atom.

Compound

Substance composed of two or more chemically bonded elemenets.

Bulk Element

Basic chemical required in abundance.

Trace Element

Basic chemical substance needed in small quantity.

Ultratrace Elemement

Basic chemical substance needed in very small quantity.

Atom

Smallest particle of an element that has the properties of that element.

Atomic Nucleus

The dense core of an atom that is composed of protons and neutrons.

Electron

A small, negatively charged particle that encircles the nucleus of an atom.

Proton

Positively charged particle in an atomic nucleus.

Neutron

Electrically neutral subatomic particle.

Atomic Number

Number of protons in an atom of an element

Mass Number

The number of protons plus neutrons in an atom's nucleus.

Isotopes

Atoms that have the same atomic number but different mass numbers.

Atomic weight

The average of the mass numbers of the isotopes of an element present.

Radioactive isotopes

Unstable isotopes that decompose, releasing energy or atomic radiation.

Atomic radiation

The energy or atomic fragments emitted by unstable isotopes (alpha, beta, and gamma).

Molecule

A particle formed by the chemical union of two or more atoms.

Molecular formula

Shorthand used to depict the numbers and types of atoms in a molecule.