Question

question 20 0.4 pts what is the number of electrons in the outermost energy level of an oxygen atom o 6 o 8 o 4 o 2 question 21 0.4 pts in the electron configuration 1s² 2s² 2p⁶ 3s¹, the 3 refers to the: o sublevel o orbital o number of electrons o energy level question 22 0.4 pts how many unpaired electrons are in a sulfur atom (atomic number 16)? o 1 o 2 o 0 o 3

Explanation:

Step1: Recall oxygen's electron configuration

Oxygen has an atomic number of 8. Its electron - configuration is $1s^{2}2s^{2}2p^{4}$. The outermost energy level is the second energy level ($n = 2$), and it has $2 + 4=6$ electrons.

Step2: Recall electron - configuration notation meaning

In the electron - configuration $1s^{2}2s^{2}2p^{6}3s^{1}$, the number before the letter represents the principal energy level. So the 3 refers to the energy level.

Step3: Determine sulfur's electron configuration and unpaired electrons

Sulfur has an atomic number of 16. Its electron - configuration is $1s^{2}2s^{2}2p^{6}3s^{2}3p^{4}$. In the $3p$ sub - level, which has 3 orbitals, according to Hund's rule, the 4 electrons fill the orbitals as follows: two orbitals have one electron each and one orbital has a pair of electrons. So there are 2 unpaired electrons.

Answer:

Question 20: 6
Question 21: energy level
Question 22: 2