The periodic table contains informative cells for each element arranged by increasing atomic number and chemical properties. Each element's cell typically contains:
- The element's symbol. Symbols are the abbreviations of the element's name. In some cases, the abbreviation comes from the element's Latin name.
- The element's atomic number. This number is the number of protons an atom of this element contains. The number of protons is the deciding factor when distinguishing one element from another.
- The element's atomic mass in atomic mass units. This number is a weighted average mass of the element's isotopes.
- The element's name. Many periodic tables will include the name to help those who may not remember all the symbols for elements.
The horizontal rows are called periods. Each period indicates the highest energy level the electrons of that element occupies at its ground state.
The vertical columns are called groups. Each element in a group has the same number of valence electrons and typically behave in a similar manner when bonding with other elements. The bottom two rows, the lanthanides and actinides all belong to the 3B group and are listed separately.
Many periodic tables identify element types using different colors for different element types. These include the alkali metals, alkaline earths, basic metals, semimetals, transition metals, nonmetals, lanthanides, actinides, halogens and noble gases.
A good periodic table is a great tool for solving chemistry problems. You can use an online periodic table or print your own.
When you feel comfortable with the parts of the periodic table, take a quick 10-question quiz to test yourself on how well you can use the table.