Question

which of the following has 50 protons, 38 neutrons, and 50 electrons?
$_{88}^{226}ra$
$_{50}^{88}sn$
$_{38}^{50}v$
$_{12}^{88}mg$
$_{38}^{88}sr$

Explanation:

Step1: Recall atomic number concept

The atomic number (Z) is equal to the number of protons. Here, the number of protons is 50, so the atomic number of the element is 50.

Step2: Recall isotope notation

In the isotope notation $^{A}_{Z}X$, where $A$ is the mass - number (sum of protons and neutrons), $Z$ is the atomic number, and $X$ is the chemical symbol of the element. The mass - number $A=50 + 38=88$ (since number of protons = 50 and number of neutrons = 38).

Step3: Identify the element

The element with atomic number 50 is tin, with the symbol $Sn$. The isotope is $^{88}_{50}Sn$.

Answer:

$^{88}_{50}Sn$ (corresponding to the option $\ _{50}^{88}Sn$ in the multiple - choice list)