How many electrons are there in the outermost shell of a potassium (K) atom that has a total of 19 electrons?

Question

a.
2

b.
8

c.
8

d.
1

Answer 1

Potassium (K) has an atomic number of 19, which means it has 19 electrons. The electron configuration of potassium is:

• 2 electrons in the first shell (1s²)
• 8 electrons in the second shell (2s² 2p⁶)
• 8 electrons in the third shell (3s² 3p⁶)
• 1 electron in the fourth shell (4s¹)

The outermost shell of potassium is the fourth shell, which has a total of 1 electron. Therefore, the correct answer is:

d. 1