Question

Which element has three unpaired electrons in its p orbital? carbon (atomic number 6) oxygen (atomic number 8) nitrogen (atomic number 7) beryllium (atomic number 4)

Answer 1

Answer: N (atomic number 7)

Explanation:

1) Due the electron distribution of each, taking into account Hund's rule to deal with pairing of electrons.

2) Hund's rule: each subshell orbital is occupied with single electrons of parallel spin before double occupation occurs.

That is, before any one orbital is doubly occupied, every orbital in a subshell is singly occupied with one electron, and all the electrons in singly occupied orbitals have the same spin, which means that they are unpaired.

3) Distributions:

a) C (atomic number 6) ⇒ 6 electrons:

⇒ 1s² 2s² 2p² ⇒ 1s² 2s² 2p ↑ ↑ : as per Hund's rule the two electrons on 2p are unpaired.

b) O (atomic number 8) ⇒ 8 electrons

⇒ 1s² 2s² 2p⁴ ⇒ 1s² 2s² 2p⇅ ↑ ↑: as per Hund's rule the two 2p electrons are unpaired

c) N (atomic number 7) ⇒ 7 electrons

1s² 2s² 2p³ ⇒ 1s² 2s² 2p↑ ↑ ↑: as per Hund's rule, the three 2p electrons are unpaired, so this is the answer to the question.

c) Be (atomic number 4) ⇒ 4 electrons

⇒ 1s² 2s² ⇒ none p electron.

Answer 2

The element has three unpaired electrons in its p orbital is nitrogen (atomic number 7). Nitrogen can also bond with other three atoms because of its outer shell (valence shell) that has three electrons. This is the reason why organic molecules can be so large because of this bonding. Suppose you have a compound of NH3. You know that hydrogen can only share 1 electron because 7 of its electrons are filled. Also, in nitrogen, it can only share 3 electrons because 5 of it are already filled. That is why nitrogen needs three hydrogen to form NH3.