Question

What are isotopes of an element?
(A) Atoms of a different element with a different number of neutrons
(B) Atoms of a different element with a different number of protons
(C) Atoms of the same element with a different number of neutrons
(D) Atoms of the same element with a different number of protons

Answer 1

The number of protons in the nucleus of every atom of a chemical element is known as the atomic number or proton number (symbol Z). A chemical element's atomic number is the only way to identify it. It is the same as the nucleus' charge number. The atomic number is also equivalent to the number of electrons in an uncharged atom.

Complete answer:
Isotopes are two or more types of atoms with the same atomic number (number of protons in their nuclei) and periodic table position (and so belong to the same chemical element) but distinct nucleon numbers (mass numbers) owing to varying numbers of neutrons in their nuclei. While all isotopes of the same element have almost identical chemical characteristics, their atomic weights and physical attributes differ. An isotope of a chemical element is an atom with a different number of neutrons (and hence a different atomic mass) than the element's standard. The atomic number refers to the number of protons in the nucleus of an atom. The atomic number is the number of protons in the nucleus of an atom, which is equivalent to the number of electrons in a neutral (non-ionized) atom. Each atomic number identifies a specific element, but not an isotope; the number of neutrons in an atom of a given element can vary widely. The mass number of an atom is determined by the amount of nucleons (both protons and neutrons) in its nucleus, and each isotope of a particular element has a distinct mass number. Carbon-12, carbon-13, and carbon-14, for example, are three carbon isotopes with mass numbers of 12, 13, and 14, respectively. Carbon has an atomic number of 6, which implies that every carbon atom has 6 protons, giving these isotopes neutron numbers of 6, 7, and 8, respectively.
As a result, option C is accurate.

Note:
An isotope's (nuclide's) atomic mass is mostly dictated by its mass number (i.e. number of nucleons in its nucleus). The binding energy of the nucleus (see mass defect), the tiny difference in mass between proton and neutron, and the mass of the electrons associated with the atom all contribute to minor corrections. The latter is owing to the fact that the electron:nucleon ratio varies among isotopes.
A dimensionless quantity is the mass number. The atomic mass is calculated using the atomic mass unit, which is based on the mass of the carbon-12 atom. The symbols "u" (for unified atomic mass unit) or "Da" (for dimensional atomic mass unit) are used to represent it (for dalton).