The periodic table is arranged such that elements in the same column share many chemical properties, including:
1) The atoms arranged in the far left and far right columns of the periodic table are non-reactive.
2) Atoms in the column with oxygen and sulfur are 4 electrons short of having a full outer shell.
3) Atoms in the column with nitrogen and phosphorus are likely to become ions.
4) Atoms in the column with hydrogen have only one electron in their outermost shell.