Chemistry

The smallest particle of an element that retains its identity in a chemical reaction

An instrument used to generate images of individual atoms

English Chemist and schoolteacher who formulated a theory to describe the structure and chemical reactivity of matter in terms of atoms

Greek philosopher who was among the first to suggest the existence of atoms

Negatively charged subatomic particles

stream of electrons produced at the negative electrode of a tube containing a gas at low pressure

Positively charged subatomic particles

Subatomic particles with no charge

the central core of an atom, which is composed of protons and neutrons

the number of protons in the nucleus of an atom of an element

an arrangement of elements according to similarities in their properties

equals the number of neutrons plus the number of protons in an atom

A vertical column of elements in the periodic table

atoms that have the same number of protons but different numbers of neutrons

1/12 the mass of a carbon-12atom

weighted average mass of the atoms in naturally occurring sample of an element

A horizontal row of the periodic table