Lecture 23 question

[Jazlyn Romero 1I]

Hello! I am currently watching today's lecture and around 4:50, Dr. Lavelle shows the orbitals for nitrogen. He includes 2s and 2p, however, I was wondering why is 1s not included? Wouldn't the 1s hold 2 electrons, and then the 2s hold another 2 electrons, and the 2p orbital will hold 1?

[shevanti_kumar_1E]

You are correct the 1s would hold 2 electrons. I think he doesn't mention the 1s because we are mainly concerned with the valence electrons, so he draws out the 2s and 2p orbital in the lecture.

[clairehathaway 2J]

Hi! I think that only the orbitals in the second shell are shown because they hold the valence electrons which are the most important in this case. I'm not 100% on this though!

[Samudrala_Vaishnavi 3A]

The electrons that we count in Lewis structures directly translate into determining the shape of molecules and these electrons that we count are outer valence electrons. The 1s orbital isn't considered an outer shell and just forms the basis of how strong the ionization energy is compared to the size of an atom. It has no relevance to the shape or structure of the molecules that we see and don't play a role in hybridization.

[AnnaNovoselov1G]

The valence electrons are the ones responsible for molecular shape because they are the ones that actually determine bonding. The n=1 shell is not the valence shell; the n=2 shell is so we only consider the subshells in that shell.

[Alexandra Salata 2L]

it's because the we are only concerned with the 2s and 2p orbitals in this example because we can assume that the 1s orbital is already filled when you look at nitrogen on the periodic table.