BMAT question - Chemical Bonds / Chemistry

Practice Question Solving
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I thought 3 electrons will be involved but the answer says 5 electrons. I know there are 3 electrons forming the bond and a lone pair for Nitrogen. Any explanation?

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Hi!
Nitrogen has five electrons, all 5 will be used to bind to the three oxygens around it (each oxygen has 2 electrons it needs to acquire). One electron forms a single bond to an oxygen atom (which will use its other electron to bind the hydrogen, two electrons form a double bond to an oxygen atom and two electrons form a bond to an oxygen atom.
Hope it helps.