In chemical reactions, atoms react and combine with other atoms to form molecules, or molecules are separated into different atoms, but the elements involved do not themselves change. Nuclear reactions actually involve the formation of different elements from the starting elements. Fission and fusion reactions are nuclear reactions. Fission reactions involve the splitting of the nucleus of an atom into nuclei of lighter atoms. This process releases energy. Fusion reactions occur when light nuclei combine to form a heavier nucleus. The energy that powers the Sun comes from combining 4 hydrogen atoms into 1 helium atom. The helium atom that results weighs less than the sum of the 4 hydrogen atoms that combined to produce it.
1. The reaction that occurs in the Sun can best be described as
a. a fission reaction because energy is released.
b. a fusion reaction because nuclei are combining to form a heavier nucleus.
c. a chemical reaction because the atoms involved in the reaction do not change.
d. both a fission reaction because energy is released and a fusion reaction because the hydrogen atom fuses into a new element.
e. a non-nuclear fusion reaction.