Difficulty: Easy
Correct Answer: The nucleus of a hydrogen atom of mass number 1 (one proton only)
Explanation:
Introduction / Context:
In atomic structure, the proton is one of the fundamental particles that make up the nucleus. Hydrogen, the simplest element, has a special role because its most common isotope consists of a nucleus with just one proton and no neutrons, surrounded by one electron. This question asks you to relate the idea of a single proton to the nucleus of specific atoms or particles, including hydrogen, helium, alpha particles and beta particles. Understanding this relationship helps in nuclear chemistry, mass spectrometry and many basic models of the atom.
Given Data / Assumptions:
Concept / Approach:
The nucleus of a hydrogen atom of mass number 1 consists of a single proton. When the electron is removed, what remains is simply a proton. Therefore, a proton can be described as a hydrogen 1 nucleus. It is not correct to equate a proton with an alpha particle or with the nucleus of helium, since those contain more than one nucleon. Beta particles are a different kind of particle entirely. The approach is to match the definition of a proton with the nucleus that contains exactly one proton and no neutrons, which is the hydrogen 1 nucleus.
Step-by-Step Solution:
Step 1: Recall that the hydrogen atom with mass number 1 has a nucleus consisting of one proton and no neutrons.
Step 2: If the electron is removed from this hydrogen atom, the remaining particle is a bare proton.
Step 3: Therefore, a single proton is identical to the nucleus of hydrogen 1, sometimes called the protium nucleus.
Step 4: Consider helium 4, which has two protons and two neutrons; its nucleus is too large to be a single proton.
Step 5: An alpha particle is a helium 4 nucleus and includes four nucleons, not one, so it is not identical to a proton.
Step 6: A beta particle is usually an electron or a positron, which has a different mass, charge and identity from a proton.
Verification / Alternative check:
Chemical notation often writes the proton as 1H plus, which emphasises that the proton is the ion formed when a neutral hydrogen 1 atom loses its electron. Mass spectrometry and nuclear reaction equations also treat 1H plus and the proton as equivalent. In contrast, an alpha particle is written as 4He2 plus, clearly showing two protons and two neutrons. Beta particles are written as 0e minus or 0e plus, indicating electrons or positrons with almost zero mass number. These standard symbols confirm that the closest and correct identification of a proton is with the nucleus of a hydrogen 1 atom.
Why Other Options Are Wrong:
Option A describes the nucleus of helium 4, which contains two protons and two neutrons and is therefore much more massive than a single proton. Option C describes an alpha particle, which is the same as the helium 4 nucleus and again contains four nucleons. Option D describes a beta particle, which is either an electron or positron, not a proton, and has a different charge to mass ratio. Option E describes the nucleus of deuterium, hydrogen 2, which has one proton and one neutron, not just a single proton. Only option B correctly states that a proton is identical to the nucleus of a hydrogen atom of mass number 1.
Common Pitfalls:
Students sometimes confuse alpha particles with protons because both carry positive charge, but alpha particles carry two positive charges and have much greater mass. Another common confusion is between hydrogen 1 and deuterium; both are isotopes of hydrogen but their nuclei differ in neutron content. Remember that a proton on its own is the bare nucleus of hydrogen 1 only. Keeping track of mass number and atomic number for each particle or nucleus will help avoid errors in nuclear chemistry questions.
Final Answer:
A single proton is identical to The nucleus of a hydrogen atom of mass number 1 (one proton only), which is the protium nucleus with no neutrons.
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