Asample of nitrogen occupies a volume of 300.0 ml under a pressure of 380.0 torr at -177c. what volume would
the gas occupy at stp?

i) 1s²2s²2p⁶3s²3p³

ii) [Ne]3s²3p³

iii) ↑↓       ↑↓    ↑↓  ↑↓  ↑↓       ↑↓   ↑ ↑ ↑

    1s²      2s²         2p⁶             3s²    3p³    

Explanation:

i) The phosphorus, with atomic number (Z) 15, has the following  electron configuration:

Z=15 → Number of electrons = 15

1s²2s²2p⁶3s²3p³  

ii) The noble gas configuration of the phosphorus is the next:

[Ne]3s²3p³  

Neon is the noble gas that precedes phosphorus, its atomic number is 10. Therefore, the first ten electrons in the electronic configuration of P correspond to the noble gas Ne.  

iii) The orbital configuration of the P is given by the spins of the electrons in each orbital:

   ↑↓            

1   s²

   ↑↓      ↑↓  ↑↓  ↑↓

2  s²             p⁶  

   ↑↓        ↑ ↑ ↑

3  s²           p³  

Where ↑ and ↓ represents electron spins.

We can consider every orbital as a box that contains the electrons, and using the Pauli exclusion principle we can fill the boxes with the electrons.

So, following that principle, we have that every box will have a maximum of two electrons, which are represented as ↑↓, when they are paired up, and ↑ when they are not paired up.          

In phosphorous case, every s orbital contain 2 electrons represented as ↑↓, and every p orbital has three orbitals: , and , for a total of 6 electrons (two electrons for each orbital), except for the 3p orbital, which has only 3 electrons, represented as ↑ ↑ ↑.                                  

I hope it helps you!