17 terms

atoms,molecules and the periodic table study guide

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atom
the smallest particle of an element
molecule
a combination of two or more atoms
chemical bond
the force that holds two atoms together
element
a substance that cannot be broken down into other substances by chemical or physical means
compound
a substance made of two or more elements chemically combined
atomic mass
the average mass of one atom of an element
periodic table
a chart of the elements showing the repeating pattern of there properties
nucleus
the central core of an atom containing protons and neutrons
proton
a small, positively charged particle in the center of and atom
neutron
a small particle in the nucleus of an atom,with no charge (neutral)
electron
a tiny, negatively charged particle that moves around the nucleus of an atom
atomic mass unit (amu)
a unit used to measure the mass of particles in atom
atomic number
the number of protons in the nucleus of an atom
chemical symbol
a one or two letter represantation of an element
family
elements in the same vertical column of the periodic tabel
(also called group)
period
a horizontal row of elements in the periodic table
valence electron
one of the electrons farthest away from the nucleus of the atom
involved in chemical reactions