Question

A particular atom has 58 protons and 82 neutrons. What are the atomic number, mass number, and periodic table symbol of this isotope?

Answer 1

Atomic Numbers are the number of protons within the nucleus,
which is 58 here.
Atomic Number=58
Mass Number is the sum of the protons and neutrons in the nucleus, 
=58+82
Mass Number=140
Periodic symbol of this isotope is entirely dependent on the number of protons, 58, which corresponds to the element Cerium, abbreviated as Ce in the periodic table. 
Periodic Symbol=Ce