Practice 14
the mass of a proton is approximately
1) 1/2000 times the mass of a neutron and a unit positive charge
2) 1/2000 times the mass of a neutron and a unit negative charge
3) 2000 times the mass of an electron and a unit positive charge
4) 2000 times the mass of an electron and a unit negative charge

3) 2000 times the mass of an electron and a unit positive charge

Explanation:

The  proton is approximately 2000 times massive than electron.

Neutron and proton are present inside the nucleus. Proton has positive charge while neutron is electrically neutral. Proton is discovered by Rutherford while neutron is discovered by James Chadwick in 1932.

Symbol of proton= P+  

Symbol of neutron= n0  

Mass of proton=1.672623×10-27 Kg

Mass of neutron=1.674929×10-27 Kg

An atom consist of electron, protons and neutrons. Protons and neutrons are present with in nucleus while the electrons are present out side the nucleus.

The electron is subatomic particle that revolve around outside the nucleus and has negligible mass. It has a negative charge.

Symbol= e-

Mass= 9.10938356×10-31 Kg

It was discovered by j. j. Thomson in 1897 during the study of cathode ray properties.

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