Four atoms of hydrogen combine to form an atom with a release of energy of\

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Professor PC Thomas Classes · Answer

The fusion reaction in the sun is a multi process in which hydrogen is buried into helium hydrogen being the fuel and helium the ashes. proton-proton (p,p) cycle by which this occurs represented by the following sets of reactions:\ ${ }_{1}^{1} \mathrm{H}+{ }_{1}^{1} \mathrm{H} ightarrow{ }_{1}^{2} \mathrm{H}+\mathrm{e}^{+}+\mathrm{v}+0.42 \mathrm{MeV}$\ $\mathrm{e}^{+}+\mathrm{e}^{-} ightarrow \gamma+\gamma 1.02 \mathrm{MeV}$\ ${ }_{2}^{1} \mathrm{He}+{ }_{1}^{1} \mathrm{H} ightarrow{ }_{2}^{3} \mathrm{He}+\gamma+5.49 \mathrm{MeV}$ $$ { }_{2}^{3} \mathrm{He}+{ }_{2}^{3} \mathrm{He} ightarrow{ }_{2}^{4} \mathrm{He}+{ }_{1}^{1} \mathrm{H}+{ }_{1}^{1} \mathrm{H}+12.86 \mathrm{MeV} $$ For the fourth reaction to occur, the first three reactions must occur twice, in which case two light helium nuclei unite to form ordinary helium or nucleus. If we consider the combination\ $2(\mathrm{i})+2(\mathrm{ii})+2(\mathrm{iii})+(\mathrm{iv})$, the net effect is\ $4{ }_{1}^{1} \mathrm{H}+2 \mathrm{e}^{-} ightarrow{ }_{2}^{4} \mathrm{He}+2 \mathrm{v}+6 \gamma+26.7 \mathrm{MeV}$\ Thus, four hydrogen atoms combine to form an ${ }_{2}^{4} \mathrm{He}$ atom with a release of 26.7 MeV of energy.\