Account for the following limit your answer to two sentence Atomic weight of most of the elements are fraction ?

Account for the following. limit your answer to two sentences: 'Atomic weight of most of the elements are fractional'.

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

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

Define atomic weight and atomic number of an element

Which of the following is the correct squence of atomic weights of given elements?

Which of the following is the correct squence of atomic weights of given elements?

Why are atomic masses of most of the elements fractional and not whole numbers?