How many hydrogen nuclei are required to form a single helium nucleus?
The correct answer and explanation is:
Correct Answer: 4 hydrogen nuclei are required to form a single helium nucleus.
Explanation:
In the process of nuclear fusion, which powers stars like the Sun, hydrogen nuclei (protons) combine to form helium nuclei. This process occurs in several steps, but the overall result is the conversion of four hydrogen nuclei into one helium nucleus.
Each hydrogen nucleus contains one proton. A helium nucleus (also called an alpha particle) contains two protons and two neutrons. During the fusion process, two of the four protons are converted into neutrons through a process called beta-plus decay. This transformation involves the emission of a positron and a neutrino. The remaining two protons stay as they are. Together, the two protons and two neutrons form the helium nucleus.
The full sequence of reactions in the proton-proton chain (dominant in the Sun) is complex and involves intermediate isotopes and particles, but the net result simplifies to this:
- 4 hydrogen nuclei (protons) come together
- 2 protons are converted into neutrons
- A helium nucleus (2 protons + 2 neutrons) is formed
- Energy is released in the form of gamma rays, neutrinos, and positrons
This fusion process releases a tremendous amount of energy. It is the primary source of the Sun’s light and heat. The mass of the resulting helium nucleus is slightly less than the total mass of the four original hydrogen nuclei. This lost mass is converted into energy, according to Einstein’s equation, E = mc².
In conclusion, it takes four hydrogen nuclei to form one helium nucleus, and the fusion process is fundamental to stellar energy production and to the synthesis of heavier elements in stars.