The atomic number is the number over the symbol of the element in the periodic table and the atomic mass the number under it. An isotope is an atom with more or less neutrons than its regular form. a neon atom with mass number of 22 will have 12 neutrons in the nucleus and 10 protons, draw it with its 10 electrons. Two electrons go in the first level of energy and eight in the second. Draw a nucleus with 10 protons and 12 neutrons and an arc with 2 electrons around it and another arc with 8 electrons over the first arc.
