how closely a measurement aligns with a correct value

inner transition metal in the bottom of the bottom two rows of the periodic table

element in group 1

element in group 2

positively charged particle consisting of two protons and two neutrons

negatively charged atom or molecule (contains more electrons than protons)

smallest particle of an element that can enter into a chemical combination

average mass of atoms of an element, expressed in amu

unit of mass equal to 1/12 of the mass of a carbon-12 atom

number of protons in the nucleus of an atom