Answer: Option (2) is the correct answer.
Step-by-step explanation:
Number of protons present in an atom represent the atomic number of atom. Also it is known that for a neutral atom number of protons equal the number of electrons.
Potassium is a group 1 element which is also known as alkali metal group. Atomic number of potassium is 19 and its electronic configuration is 2, 8, 8, 1.
This means that valency of potassium is 1.
Hence, we can conclude that the total number of electrons in an atom of potassium are 19.