Reading from left to right, they are arranged in increasing atomic number (protons )
Each period (going across) increases in atomic number
As you go down a period, they have one more ring of electrons
As you go down a column, called groups, the elements have the same number of valence electrons, which gives them similar chemical activity
Metals are on the left, nonmetals on the right and metalloids along the zig-zag line that divides the metals and nonmetals, inert gases on the far right
In general the elements do get heavier as you increase atomic number, but there are variances
