- Books Name
- Science Made Easy Science Book
- Science Made Easy
- CBSE Class 9
Discovery of Neutrons (By J. Chadwick)
→ J. Chadwick bombarded lighter elements (like lithium, boron etc.) with α-particles and observes
emission of new particles having zero charge but having mass equal to that of proton.
→ These particles were called ‘Neutron’ i.e., neutral particle of the atom.
→ Neutron are absent in Protium isotope of hydrogen atom.(1H1)
→ Since, mass of electrons are negligible as compared to that of proton and neutrons hence, sum
of masses of protons and neutrons in an atom will compose its atomic mass.