Let's break down the question step-by-step based on the information provided:
1. Understanding an Alpha Particle:
- An alpha particle consists of 2 protons, 2 neutrons, and no electrons.
2. Interpreting the Table:
- The table lists neutral, low-mass atoms with information about their element name, symbol, atomic number (number of protons), and number of neutrons.
3. Identifying the Matching Isotope:
- We need to find an element with 2 protons and 2 neutrons.
- According to the table:
- Hydrogen (H): 1 proton, 0 neutrons.
- Helium (He): 2 protons, 2 neutrons.
- Lithium (Li): 3 protons, 4 neutrons.
- Beryllium (Be): 4 protons, 5 neutrons.
4. Conclusion:
- The element that matches the criteria of having 2 protons and 2 neutrons is Helium.
- Specifically, Helium with 2 protons and 2 neutrons is known as the isotope helium-4.
Therefore, an alpha particle is also referred to as a nucleus of the isotope helium-4.
