What is atomic mass, atomic number, isotopes and how are all these terms related to each other?

Atomic mass is the sum of proton and neutrons

Atomic number is just number of protons

Isotopes of elements have same atomic number but different atomic mass due to difference in number of nuetrons

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.