Concept:The atomic nucleus is the tiny, dense, positively charged centre of an atom. It is made up of protons and neutrons, while electrons orbit around it.
Explanation:An atom has two main parts: the nucleus and the electron cloud.
The nucleus contains protons (positive charge) and neutrons (neutral charge).
Electrons (negative charge) are not in the nucleus; they move in regions outside it.
This structure was discovered by Ernest Rutherford in 1911 using the gold foil experiment.
The nucleus is extremely small — its radius is only about 1/100,000 of the atom’s total radius.
Thus, among the given options, only "protons and neutrons" correctly describe the composition of the nucleus.
Answer:Option B: protons and neutrons