Question

how many protons and neutrons are in an atom of $^{209}$bi?
number of protons =
number of neutrons =

Explanation:

Step1: Find atomic number of Bi

Bismuth (Bi) has an atomic number of 83, so number of protons = atomic number = 83.

Step2: Calculate number of neutrons

Mass number (209) = number of protons + number of neutrons. So number of neutrons = mass number - number of protons = 209 - 83 = 126.

Answer:

Number of protons = 83, Number of neutrons = 126