The mass number of [tex]$Fe ^{2+}$[/tex] is 56. How many neutrons are there in a single [tex]$Fe ^{2+}$[/tex] atom?
A. 28
B. 30
C. 56
D. 58
Answer (1)
The mass number (A) is the sum of protons (Z) and neutrons (N): A = Z + N .
Iron (Fe) has an atomic number (Z) of 26.
Calculate the number of neutrons (N) using N = A − Z = 56 − 26 .
The number of neutrons in a single F e 2 + atom is 30 .
Explanation
Problem Analysis We are given that the mass number of F e 2 + is 56. We need to find the number of neutrons in a single F e 2 + atom. The 2 + charge indicates that the atom has lost two electrons, but this does not affect the number of protons or neutrons in the nucleus.
Mass Number Equation The mass number (A) is the sum of protons (Z) and neutrons (N), so we have the equation: A = Z + N
Atomic Number of Iron For Iron (Fe), the atomic number (Z) is 26. This means that there are 26 protons in the nucleus of an iron atom.
Finding Number of Neutrons We are given the mass number A = 56 . We can find the number of neutrons (N) using the formula: N = A − Z
Substitution Substitute the values of A and Z into the equation: N = 56 − 26
Calculation Calculate the number of neutrons: N = 30
Final Answer Therefore, there are 30 neutrons in a single F e 2 + atom.
Examples
Understanding the number of neutrons in an atom is crucial in various fields. For example, in nuclear medicine, isotopes of iron with different numbers of neutrons are used in diagnostic imaging and therapeutic treatments. Knowing the neutron count helps scientists predict the stability and radioactive properties of these isotopes, ensuring safe and effective medical applications. Also, in material science, controlling the neutron count in iron alloys can modify their mechanical properties, such as strength and corrosion resistance, leading to improved engineering designs.
