Question 17

Atom is the basic building block of matter.

An atom is defined as the smallest unit of matter that retains the properties of an element. It serves as the fundamental building block for all substances in the universe.

A) Neutron

While neutrons are subatomic particles found within the nucleus of an atom, they are not the basic building block of matter. Neutrons contribute to the mass of an atom, but they do not represent the smallest unit that defines the properties of matter.

B) Atom

The atom is indeed the basic building block of matter, as it is the smallest unit that can exist independently and still retain the characteristics of an element. Atoms combine in various ways to form molecules, which make up all physical substances.

C) Element

An element is a pure substance that consists of only one type of atom. While elements are composed of atoms, they are not the fundamental building blocks themselves; rather, they are collections of identical atoms.

D) Electron

Electrons are negatively charged subatomic particles that orbit the nucleus of an atom. Although they are crucial for chemical bonding and reactions, they are not the basic unit of matter, as they do not exist independently as complete entities.

Conclusion

The atom is the definitive answer to the question of what constitutes the basic building block of matter, as it encapsulates the essential characteristics and properties of elements. All other options either refer to subatomic particles or collections of atoms, making them incorrect in this context.