Answer:
[tex]^{55} _{26}Fe[/tex]
Explanation:
Let's consider the following nuclear equation.
[tex]^{55} _{25}Mn + ^{2} _{1}H \rightarrow \_\_\_ + 2^{1} _{0}n[/tex]
According to the law of conservation of matter, all the matter that is on the reactants must be in the products.
Mn has 25 protons and H has 1 proton. Therefore, in the products there must be 26 protons. The neutrons do not have protons, so the 26 protons belong to the unknown element. (The only option with 26 protons is c) Fe).
Mn has 55 -25 = 30 neutrons. H has 2 - 1 = 1 neutron. The total number of neutrons is 31. There are 2 neutrons to the right so Fe must have the remaining 29.
The mass number of Fe is 26 p⁺ + 29 n⁰ = 55. This confirms that the missing element is [tex]^{55} _{26}Fe[/tex].
