Answer:
a. The atomic mass
Step-by-step explanation:
The periodic table gives multiple different pieces of information about each element.
Representing Information
On the periodic table, there are 3 main pieces of information. In the center of each square, there is an atomic symbol. The atomic symbol is 1 or 2 letters that show the abbreviation of the element. Below the atomic symbol is the atomic mass. Since the atomic mass is an average value, it is usually a number that has decimal points. Above the atomic symbol is the atomic number. The atomic number is the number of protons in an atom. Across the periodic table, atomic numbers go up by one.
Atomic Mass
Atomic mass the average mass of different isotopes. Atomic mass is given in grams per mole. So, it represents the mass of one mole of the element. Since different isotopes have different masses, the atomic mass reported on the periodic table is the average mass of the element. Additionally, since average mass has to be measured by machines, different periodic tables tend to have slightly different reported atomic masses.