Answered

All large radioactive atoms decay into smaller atoms by releasing alpha particles. Each alpha particle has 2 protons, 2 neutrons, and 0 electrons. The table below describes several neutral, low-mass atoms.

\begin{tabular}{|l|l|l|l|}
\hline \multicolumn{4}{|c|}{ Stable Isotopes of Low-Mass Elements } \\
\hline Element Name & Symbol & \begin{tabular}{l}
Atomic \\
Number
\end{tabular} & \begin{tabular}{l}
Number of \\
Neutrons
\end{tabular} \\
\hline Hydrogen & [tex]$H$[/tex] & 1 & 0 \\
\hline Helium & [tex]$He$[/tex] & 2 & 2 \\
\hline Lithium & [tex]$Li$[/tex] & 3 & 4 \\
\hline Beryllium & [tex]$Be$[/tex] & 4 & 5 \\
\hline
\end{tabular}

An alpha particle is also referred to as the nucleus of which isotope?

A. lithium-7
B. helium-4
C. hydrogen-2
D. helium-2



Answer :

GinnyAnswer
Let's carefully examine the given details:

1. Definition of an Alpha Particle:
An alpha particle is described as having 2 protons, 2 neutrons, and 0 electrons. This particle is essentially the nucleus of a helium-4 atom without any electrons.

2. Atomic Composition:
- Protons determine the atomic number of an element.
- Combining the protons and neutrons gives the mass number of the element.

3. Isotope Clarification:
- Lithium-7:
- Atomic Number: 3 (3 protons)
- Number of Neutrons: 4
- Total Mass: 7 (3 protons + 4 neutrons)

- Helium-4:
- Atomic Number: 2 (2 protons)
- Number of Neutrons: 2
- Total Mass: 4 (2 protons + 2 neutrons)

- Hydrogen-2 (Deuterium):
- Atomic Number: 1 (1 proton)
- Number of Neutrons: 1
- Total Mass: 2 (1 proton + 1 neutron)

- Helium-2:
- Atomic Number: 2 (2 protons)
- Number of Neutrons: 0
- Total Mass: 2 (2 protons + 0 neutrons)

Given the above clarifications, an alpha particle fits the description of an isotope with 2 protons and 2 neutrons.

Conclusion:
Among the options provided, the only isotope that matches the description of having 2 protons and 2 neutrons is helium-4.

Therefore, the correct answer is:

Helium-4