Question

the ground state electron configuration of a neutral k atom is
answer:
a $1s^{2}2s^{2}2p^{6}3s^{2}$
b $1s^{2}2s^{2}2p^{6}3s^{1}$
c $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}$
d $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{1}$
e $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{1}$

Explanation:

Step1: Determine the atomic number of K

The atomic number of potassium (K) is 19. So, a neutral K atom has 19 electrons.

Step2: Write the electron configuration using the Aufbau principle

• Fill the \(1s\) orbital first: \(1s^{2}\) (2 electrons used, 17 left)
• Then \(2s\): \(2s^{2}\) (4 electrons used, 15 left)
• Then \(2p\): \(2p^{6}\) (10 electrons used, 9 left)
• Then \(3s\): \(3s^{2}\) (12 electrons used, 7 left)
• Then \(3p\): \(3p^{6}\) (18 electrons used, 1 left)
• Finally, the last electron goes to the \(4s\) orbital: \(4s^{1}\)

So the electron configuration is \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{1}\)

Answer:

E. \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{1}\)