The atomic number is usually found in the upper left-hand corner or directly over the element's symbol within an element box on the periodic table. The atomic number will be represented as an integer. The atomic number is the number of protons within an atom of the element. Atomic numbers are what make one element different from one another. Potassium has an atomic number of 19.
The atomic mass, the element symbol, and the element's name can also be found within an element box on the periodic table. The element's symbol is found in the center of the element box. An element's symbol is composed of one or two letters. If an element symbol is made of two letters, the first is capitalized and the second is not. The element's name is found below the element's symbol. Depending on the periodic table that is used, the atomic mass is sometimes referred to as the atomic weight and is found directly below the element symbol and name. This number represents the average mass of the atoms of that element.