Consider the symbol subscript b superscript a baseline upper x where x stands for the chemical symbol for an element. what information is given by a and b?

Based on typical convention used in periodic tables, the superscript, a, located at the top of the element refers to its atomic number. The atomic number gives the number of protons of the element. On the other hand, the subscript, b, or the one on the bottom of the element gives its atomic mass. The atomic mass is approximately equal to the number of protons and neutrons in the atom of the element.