Why is the atomic mass of chlorine taken as 35.5 u and not a whole number like 35 u or 36 u. Explain

Answer: Due to the involvement of isotopes, the atomic weight of chlorine would be 35.5u rather than 35u. Isotopes are variants of a specific element that share the very same count of protons and though different numbers of neutrons inside the atom. Taking into account a chlorine atom, which has 17 protons and two isotopes, chlorine-35, as well as chlorine-37.

In 37 – Chlorine

There are 17 protons and 20 neutrons in the universe. It occurs approximately 75% of the time in nature. 37. Chlorine. There are 17 protons and 20 neutrons in the universe. It happens about 25% of the time in nature.

Atomic mass is the total of the proton mass, neutrons, and electrons inside an atom or its group. The average mass of an element’s naturally occurring isotopes comparative to the atom’s mass of ¹²C is defined as its relative atomic mass.

 (25/100 x 37) + (75/100 x 35) = relative atomic mass

35.5 u is the relative atomic mass.

As a result, the atomic weight of chlorine is 35.5u instead of a whole number such as 36u or 35u.