HONC Atoms

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It is worth mentioning here that life depends mainly on molecules formed from four different types of atom: hydrogen, oxygen, nitrogen and carbon.
These four atoms can each make a different number of covalent bonds: hydrogen can make only one, oxygen can make two, nitrogen three and carbon can make four covalent bonds. Here we show the HONC atoms as balls with their bonds as sticks. Can you work out which atom is which? Note that, taken in order (1234), the symbols for these atoms spell the word HONC. This is one way to remember how many bonds each atom can make.
To find out why these numbers arise, click here.