The Correct Answer and Explanation is:
The correct answer is c) Electrons.
The image provides a diagram representing a basic model of an atom, often referred to as the Bohr model. This model illustrates the fundamental components of an atom and their general locations. To understand why ‘Electrons’ is the correct answer, it is essential to break down the structure of an atom as shown.
An atom is composed of a central core, the atomic nucleus, and one or more particles that orbit this nucleus. The diagram correctly labels the central part as the “atomic nucleus.” This nucleus contains two types of subatomic particles: protons and neutrons. Protons possess a positive electrical charge, while neutrons are electrically neutral, having no charge. These two particles are bound together by the strong nuclear force and constitute nearly all the mass of an atom. In the diagram, these are the spheres clustered at the very center.
The question asks to identify the particle labeled “A.” The line for label A points to one of the concentric circular paths that surround the atomic nucleus. These paths represent specific energy levels or shells where a different type of subatomic particle resides. These particles are called electrons. Electrons are extremely lightweight particles that carry a negative electrical charge. The electrostatic force of attraction between the negatively charged electrons and the positively charged protons in the nucleus keeps the electrons in orbit.
Let’s evaluate the other options.
a) Protons are located inside the nucleus, not in the orbits around it.
b) Neutrons are also confined to the nucleus alongside the protons.
d) Quarks are even more fundamental particles that are the building blocks of protons and neutrons. They are not found orbiting the nucleus independently; they are bound together within the nucleons.
Therefore, based on the standard model of an atom, the region indicated by label A is an electron shell, and the particles that occupy these shells are electrons. The arrangement and number of electrons in these shells determine an atom’s chemical properties and its ability to form bonds with other atoms.
