[Lachgas]

Hi CF,
it feels like I am going nuts. I have been told for months that the elements of the second period in the periodic table all HAVE to satisfy the octet rule. What is really driving me crazy is that I've been told numerous times that the number of bonds an atom from the second period is equivalent to: 8 - No. of valence electrons. For Nitrogen that should mean: 8-5=3 bonds max.
How can one explain N2O then? N≡N-O. The Nitrogen in the middle is forming 4 bonds which can not happen by the "formula" I stated above. Is the formula straight up bullcrap or am I overlooking something?
Also, atoms upwards from the third period can contain more than 8 VE. Does that mean they still try to get an octet or are they trying to fill their whole outer shell?

Thanks for anyone who is willing to help.

[Corribus]

What you've been told is only really valid if the formal charge on the atom is zero. Can you tell what it is for the atoms in N₂O?

[Lachgas]

What you've been told is only really valid if the formal charge on the atom is zero. Can you tell what it is for the atoms in N₂O?

0 for the left nitrogen atom, +1 for the middle nitrogen atom and -1 for the oxygen atom.

[Corribus]

Right, and can you convince yourself that each atom is surrounded by 8 electrons? Because that's what the octet rule basically requires.

[Enthalpy]

N≡N-O

Oxygen making only one bond? That's fishy.

I doubt the octet rule in the second period. Think at CO.