Introduction to Atoms
period
a horizontal row of elements in the periodic table
chemical symbol
a one- or two-letter representation of an element
energy level
a region of an atom in which electrons of the same energy are likely to be found
neutron
a small particle in the nucleus of an atom, with no electrical charge
electron
a tiny, negatively charged particle that moves around the outside of the nucleus of an atom
periodic table
an arrangement of elements showing the repeating pattern of their properties
isotope
an atom with the same number of protons but a different number of neutrons from other atoms of the same element
proton
small, positively charged particles that are found in the nucleus of an atom
atomic mass
the average mass of all the isotopes of an element
atom
the basic particle from which all elements are made
nucleus
the central core of an atom which contains protons and neutrons
atomic number
the number of protons in the nucleus of an atom
mass number
the sum of protons and neutrons in the nucleus of an atom
group
elements in the same vertical column of the periodic table; also called family