[mazdarotary13]

I was wondering if someone can help me with this problem. I would like someone to help explain the problem, not just give me the answer. much thanks, chemicalforums

[pear]

step 1: count the number of valence electrons
    H has 1 valence e- and each N has 5, so there are a total of 1 + (3x5) = 16 valence e-
step 2: arrange them in predicted order, the most electronegative atom in the center
   given by problem: H N N N
step 3: connect the atoms with a single bond
       H - N - N - N
step 4: place remaining electrons as lone pairs or as bonds around those atoms whose outer shell is incomplete
           (remember H only needs 2 [1s²])
       But Since I can't seem to find a way to show triple bonds, check out the possible answers and my reasoning.
       remember that the formal charge on each atom is it's valence electrons minus the number of e- assigned to it
       (each bond provides 1 e-; single bond = 1, double bond = 2, etc.)
            a) not a valid answer since no formal charge shown
            b) 16 e-; bonds good; H ok, N₁ ok, N₂ ok, and N₃ ok.  works.
            c) 16 e-; bonds good; H ok, N₁ ok, N₂ ok, N₃ ok.  works.
            d) 16 e-; bonds good; H ok, N₁ ok, N₂ ok, N₃ ok.  works.
            e) bonds give a total of 22 e-; not possible.
            f) bonds give a total of 18 e-; not possible.

If you're starting from scratch and aren't given them to chose from, play with the e- arrangements once each atom is connected via a single bond and check that you haven't exceeded the number of valence e-'s.

[mazdarotary13]

Ohh wow. Thanks, a lot, pear. I found that extremely helpful.