Define atomic number and mass number .

(a) What is mean by (i) atomic number, and (ii) mass number, of an element ? Explain with the help of an example (b) What is the relation between the atomic number and mass number of an element ? (c) If an element M has mass number 24 and atomic number 12, how many neutrons does its atom contain ?

Write the complete symbol for (i) the nucleus with atomic number 56 and mass number 138 (ii) the nucleus with atomic number 26 and mass number 55 (iii) the nucleus with atomic number 4 and mass number 9.

A radioactiv element has atomic number A and mass number M. It emits one alpha - particle .The atomic number and mass number of new element will be

An element of atomic number Z and mass number A, emits an alpha particle, a beta particle and gamma radiations. What is the atomic number and mass number of the daughter element ?