Question

The nucleus of an atom contains
A. Electrons and photons
B. Electrons, protons, and neutrons
C. Electrons and neutrons
D. Protons and neutrons

Answer 1

Hint: Nucleus is the central portion where all mass of an atom is concentrated. 99.99% of the mass of an atom is occupied by a nucleus. We know that like charges attract each other and unlike charges repel each other and this is nothing but electrostatic force.

Complete step-by-step answer:
We know what an atom is.
Atoms are present in molecules.
An atom is made up of electrons and nucleus. Electrons are an individual part in an atom but nucleus do have contains in it. The nucleus is made up of protons and neutrons. It is a dense central portion. The electron does revolution around the nucleus. Electrons are negatively charged. But protons have a positive charge on it and neutrons have no charge.
If equal number protons and electrons are present in an atom then an atom is said to be a neutral atom. Numbers of neutrons within an atom of a particular material can vary. An atom of the same element but having a different number of neutrons are called isotopes.
Atom is very minute therefore we cannot measure its mass in our mass units like grams or kilograms. To overcome the issue scientists invented a new mass named the Atomic Mass unit.
\[1\text{ }atomic\text{ }mass\text{ }unit=1.6605\times {{10}^{-27}}kg\]
Answer- (D)

Note: If the question is asked what is the composition of the nucleus than protons and neutrons are the compositions of the nucleus. We know that protons are positively charged whereas neutrons don't have charge on it. So the whole concentration becomes positive therefore the nucleus of an atom is positively charged. Now the question comes how protons, neutrons and electrons are held together? Electrostatic forces are responsible. There is an attraction between a negatively charged electron of an atom and positively charged proton.at the same time repulsion also takes place within protons and electrons separately.