Question

Which particle orbits an atom's nucleus? A. isotope C. proton B. neutron D. electron

Short answer

The correct particle that orbits an atom's nucleus is D. electron.

Step-by-step solution

Understanding Atomic Structure

Atoms are composed of three main particles: protons, neutrons, and electrons. Protons and neutrons form the nucleus at the center of the atom, while electrons orbit around the nucleus.

Identifying Particle Positions

Protons and neutrons are situated in the nucleus. Electrons are found in various energy levels or electron clouds surrounding the nucleus, moving at high speeds.

Selecting the Correct Option

The particle that orbits the nucleus is the electron. Among the given options, the correct choice is D. electron.

Key concepts

Protons

Protons are one of the fundamental particles that make up an atom.
They reside in the atom's nucleus, alongside neutrons. Each proton carries a positive electric charge, which is a key characteristic that affects the overall charge of an atom.
The number of protons in an atom, known as the atomic number, defines the identity of an element. For example, hydrogen has one proton, while carbon has six. Protons are incredibly important for a few reasons:

• They determine the chemical identity of an element.
• The positive charge of protons balances the negative charge of electrons, making neutral atoms.
• Their presence contributes to the mass of the atom.

Understanding protons is crucial, as changes in the number of protons can transform one element into another, a process fundamental to nuclear reactions.

Neutrons

Neutrons are neutral particles that also reside in an atom's nucleus, along with protons. Although they do not possess any electric charge, neutrons contribute significantly to the mass of an atom.
Neutrons play several critical roles:

• They add mass to the nucleus, which affects the atom's stability.
• The presence of neutrons prevents protons in the nucleus from repelling each other due to their like charges.
• Atoms of the same element can differ in the number of neutrons they possess. These variations are known as isotopes.

Understanding neutrons provides insight into isotopes, which play a vital role in fields such as medicine and archaeological dating. Despite having no charge, neutrons are essential in maintaining the structure and stability of an atom.

Electrons

Electrons are the third type of particles that make up an atom, but unlike protons and neutrons, they orbit the nucleus.
These tiny particles carry a negative charge and play a crucial role in many of an atom's properties. Here’s what makes electrons so important:

• They define the atom's size, as they occupy regions known as electron clouds.
• Electron arrangements determine how atoms interact and bond with one another, leading to the formation of molecules.
• Changes in electron configurations result in chemical reactions.

Electrons move rapidly within the electron cloud and are distributed in different energy levels. These energy levels can be thought of as the "paths" or orbitals that electrons follow around the nucleus.
Understanding electrons helps explain phenomena like electricity and magnetism, as well as many chemical processes.