Question

1. write the atomic symbol (symbol notation) for the two isotopes of uranium(u), whose atomic number is 92. one isotope has 142 neutrons, and the other isotope has 146 neutrons.

Explanation:

Step1: Recall atomic - symbol notation

The atomic - symbol notation is $_{Z}^{A}X$, where $Z$ is the atomic number, $A$ is the mass number, and $X$ is the chemical symbol. The mass number $A=Z + N$, where $N$ is the number of neutrons.

Step2: Calculate mass number for the first isotope

Given $Z = 92$ and $N_1=142$. Then $A_1=Z + N_1=92 + 142=234$. The atomic symbol for this isotope is $_{92}^{234}U$.

Step3: Calculate mass number for the second isotope

Given $Z = 92$ and $N_2 = 146$. Then $A_2=Z+N_2=92 + 146=238$. The atomic symbol for this isotope is $_{92}^{238}U$.

Answer:

$_{92}^{234}U$, $_{92}^{238}U$