Question

What is the difference between Mass Number and Atomic Mass? If an element X has a mass number of 92 and 40 protons, please explain how you could obtain the number of neutrons and electrons of this element.

Answer 1

mass number is the number of protons and neutrons inside the nucleus of an atom and it also tells us about the mass of an atom in amu or atmic mass units.....while atomic mass is the average mass of all the isotopes of a certain type..It is a weighted average that takes into account the abundances of all types of isotopes...

clearly mass no. of atom = no. of protons + no. of neutrons=92(given)

also , no. of protons = 40(given)

so , no. of neutrons = 92 - 40 = 52 neutrons...

Also for an atom , no. of protons = no. of neutrons , to maintain electrical neutrality of an atom....

hence , no. of electrons will also be 40