The Periodic Table 10/10/12

The Periodic Table

Describing the Periodic Table It arranges all the known elements in an organized chart. Elements are arranged left to right and top to bottom in order of increasing atomic number and (usually) atomic mass

Types of Elements 3 main types of elements –Metals –Metalloids –Nonmetals

Rows - elements of each row have the same number of energy levels (shells). Columns - elements have the same number of electrons in the outermost energy level or shell (one to eight).

Periods The different rows of elements are called periods. –The period number of an element shows the highest energy level that has at least one electron.

Family The different columns of elements are called groups or families –Elements in the same family have similar properties

Elements Every element has:

Atomic Number The number of protons in an atom is referred to as the atomic number of that element.

Atomic Symbol The atomic symbol is one or two letters chosen to represent an element. Ex) H is for Hydrogen

Atomic Mass The atomic mass is the average mass of an element in atomic mass units ("amu").