Question

Define atomic number and mass number. Which one of them is a more fundamental attribute of element ? State the reason.

Answer 1

atomic number is a total no. of protons present in the nucelus of atom.

 mass number is the sum of protons and neutrons present in the nucleus of atom


 atomic number fundamental attribute of element . because atomice no decides the chemical properties of an element 

Answer 2

The number of protons in the nucleus of an atom
is called the atomic number
The number of protons plus the number of neutrons
is called the mass number.