1. Chemistry Notes
Part 2

2. Periodic Table
Chemical Symbols are shortened way of writing the names of elements.
Chemical symbols are usually 1 to 2 letters. The first is always capitalized while the second is lower case. Some chemical symbols come from the latin names of the elements (Ex: Latin name for lead is plumbum so its symbols is Pb)
Order - Elements are ordered in increasing atomic mass, organized by Mendeleev. Elements with similar properties occurred periodically. (to repeat in certain pattern)
There were some problems with this order so about 50 years later they arranged elements according to atomic number. All elements within the same column have similar properties.

3. There are 18 columns in the periodic table called groups or families
There are 18 columns in the periodic table called groups or families. Elements in the same groups are similar physical and chemical properties. They also have the same number of electrons in the outer shell.
There are 7 rows called periods. With the except of period one, period elements start as a solid and end as a gas. Elements in the same period also have the same number of energy levels.