the smallest piece of an element that still represents that element
atom
the science that deals with the composition and properties of substances and various elementary forms of matter
chemistry
fluid that conforms to the shape of its container
liquid
a substance possessing perfect molecular mobility and the property of indefinite expansion
gas
having three dimensions (length, breadth, and thickness)
solid
the integer nearest in value to the atomic weight of an atom and equal to the number of nucleons in the nucleus of the atom
mass number
the group of electrons revolving around the nucleus of an atom
electron cloud
the number of positive charges or protons in the nucleus of an atom of a given element
atomic number
the elementary particles that make up the protons and neutrons that in turn make up the atomic nucleus
quarks
the substance or substances of which any physical object consists or is composed
matter
the amount of matter in an object
mass
the region in the center of an atom where most of an atom's mass and positive charge is concentrated
nucleus
a neutral particle in the nucleus of an atom
neutron
any element that spontaneously emits radiation
radioactive
found in atomic nuclei in numbers equal to the atomic number of the element
protons
a stable elementary particle present in all atoms
electrons
any of two or more forms of a chemical element
Isotopes
a process that occurs when an unstable atomic nucleus changes in to another stable nucleus
nuclear decay
the average mass of the element's isotopes
average atomic mass
a table illustrating the periodic system
periodic table