all atoms of the element potassium have 19 protons. one of the most stable types of potassium atoms has the…

all atoms of the element potassium have 19 protons. one of the most stable types of potassium atoms has the mass number 39. how many neutrons make up one of these potassium atoms? o 19 o 20 o 38 o 58

all atoms of the element potassium have 19 protons. one of the most stable types of potassium atoms has the mass number 39. how many neutrons make up one of these potassium atoms? o 19 o 20 o 38 o 58

Answer

Explanation:

Step1: Recall mass - number formula

The mass number ($A$) of an atom is the sum of the number of protons ($p$) and neutrons ($n$), i.e., $A=p + n$.

Step2: Rearrange the formula to find neutrons

We can rewrite the formula as $n=A - p$.

Step3: Substitute given values

Given that $A = 39$ and $p=19$, then $n=39 - 19$.

Step4: Calculate the number of neutrons

$n = 20$.

Answer:

20