Periodic Table
Chart to organize elements by their chemical and physical properties.
Dmitri Mendeleev
Created modern periodic table
Atomic number
Number of protons in the nucleus of an atom
ALWAYS a whole number
atomic mass
Average atomic mass.
Always a decimal.
Measured in atomic mass units (amu)
Ion charge
Electric charge that forms on an atom when it gains or looses electrons
Multiple Ion Charge
Elements that can form ions in more than one way
Metalloids
Have some of the properties of metals and some of the properties of nonmetals
Period
A row across on the periodic table
Chemical family
A vertical column where the elements have similar chemical or physical properties.