Chapter 12 Atoms and Elements Vocabulary Words and Definitions
Atom -
The smallest unit of an element that still has the properties of that
element.
Proton -
A subatomic particle that has a positive electric charge.
Nucleus -
The center of an atom, usually made of protons and neutrons.
Neutron -
A subatomic particle that has the same mass as a proton but no
electric charge.
Electron -
A subatomic particle that orbits an atom's nucleus, has a negative
charge, and has very little mass.
Atomic number - The number of protons in an atom.
Element -
A substance made up of only one kind of atom.
Metal -
A substance that conducts heat and electricity well and is
malleable.
Non-metal -
A substance that does not conduct electricity and is not malleable.
Periodic table - A table that shows the elements arranged by their atomic numbers.
Compound -
A substance made up of atoms of two or more elements that are
chemically combined.
Melting point - The temperature at which a substance changes from a solid to a
liquid.
Boiling point - The temperature at which a substance changes from a liquid to a
gas.
Plasma -
A state of matter made up of charged atoms, uncharged atoms, and
free electrons.