Answer:
Most of the mass of an atom comes from the electron cloud.
Step-by-step explanation:
All options are correct except,
Most of the mass of an atom comes from the electron cloud. Because,
Most of mass comes from nucleus in which protons and neutrons are present.
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
While 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.