Are the atomic masses of the elements their actual masses ?

Atomic mass of the element Sulphur-

Atomic mass of an element is

Atomic mass of an element is

Why does not the atomic mass of an element represemt the actual mass of its atom ?

Why are the atomic mass of most of the elements fractional ?

Are the atomic masses of some elements actually fractional ?

Are the atomic masses of some elements actually fractional ?

(a) Why does not the atomic mass of an element represent the actual mass of its atom? (b) The atomic mass of an element is in fraction. What does it mean? (c) Why is the value of Avogadros number 6.022 xx 10^(23) and not any other value? (d Does one gram mole of a gas occupy 24.4 L under all conditions of temperature and pressure?