It's an apartment building for atoms. Each row is a floor called a period. The higher the floor number, the more electron "shells" (layers) the atom has, so atoms get bigger as you go down.

Each column is a family called a group. Elements in the same column behave alike, like siblings who share the same habits. Everything in column 18 (the noble gases) is calm and barely reacts; everything in column 1 (except hydrogen) is wild and reacts with water.

The atomic number is the element's ID number. It counts the protons in the center of the atom. The whole table is sorted by it: 1, 2, 3, all the way to 118.

The symbol is a short nickname: one capital letter, sometimes followed by one small letter (Co is cobalt, but CO is a molecule!). A few come from old Latin names, like Fe from ferrum (iron) and Au from aurum (gold).