What is the difference between an element's atomic number and its atomic weight?

Video transcript

Hello. In this problem we are asked how does an element's atomic mass differ from its atomic number. Looking at the answers that were provided in a it says elements atomic mass is the sum of the number of protons and the number of neutrons. So this is incorrect. This is actually what we term in the mass number. He then says atomic mass of an element is the weighted average of the mass of all the isotopes of the element. While the atomic number is equal to the number of protons of the element. So this is correct. Continue on looking at other possible answers. She says the atomic mass an element is the mass of the most abundant isotope of element. So that's incorrect. It's a weighted average of all the isotopes and the last one says the atomic mass of an element is the mass of the heaviest isotope of element. This is also incorrect. Again, it's the weighted average of all the isotopes of the element. So the correct answer then, is B thanks for watching. Hope this helped