Question

1. write the symbols for the isotopes of uranium with the following numbers of neutrons:

a. 142 neutrons
b. 143 neutrons
c. 146 neutrons

Explanation:

Step1: Recall uranium's atomic number

Uranium (U) has an atomic number \(Z = 92\), which is the number of protons.

Step2: Calculate the mass - number for each isotope

The mass - number \(A\) of an isotope is the sum of the number of protons and neutrons (\(A=Z + N\), where \(N\) is the number of neutrons).

For part a:

Given \(N = 142\), \(A=92 + 142=234\). The symbol for the isotope is \(_{92}^{234}U\).

For part b:

Given \(N = 143\), \(A=92+143 = 235\). The symbol for the isotope is \(_{92}^{235}U\).

For part c:

Given \(N = 146\), \(A=92 + 146=238\). The symbol for the isotope is \(_{92}^{238}U\).

Answer:

a. \(_{92}^{234}U\)
b. \(_{92}^{235}U\)
c. \(_{92}^{238}U\)