1. Which is composed of matter? (6P21)

A. Electricity

B. An atom

C. Light

D. heat

An atom

Explanation:

Matter is composed of atoms and atom is further consist of smaller particles called electron, proton and neutrons.

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

The atom interact with another atom by sharing or transferring the electrons. The properties of substances are depend upon the electrons present out side the nucleus.