Answer: Option (b) is the correct answer.
Explanation:
As it is known that both sodium and potassium are same group elements. Both of then belongs to group 1A.
Since, sodium is at 11th position in the periodic table and its atomic number is also 11. Therefore, electronic distribution of sodium is 2, 8, 1.
Similarly, potassium is placed at 19th position in the periodic table and its atomic number is 19. So, electronic distribution of potassium is 2, 8, 8, 1.
It is known that valence electrons are the electrons present in the outermost shell of an atom.
So, in a potassium atom there is only one valence electron is present.
Thus, we can conclude that potassium have 1 valence electron.
