A video I watched showed the construction of a phosphate group using a Lewis structure.

The oxygen with the double bond fills its octet group. The three other oxygens lack an electron.

The teacher merely pointed out this lack and added the missing electrons (shown in red).

Phosphate group Lewis Structure in three stages

Where do these missing electrons come from? Are they stolen from passing hydrogens?

  • $\begingroup$ A person with net worth above $1\,000\,000\,000\;\$$ is called a billionaire. Where do these money come from? It does not matter. Same thing here. $\endgroup$ Sep 6 '20 at 19:21
  • $\begingroup$ Do you mean my question was not worth asking? $\endgroup$
    – Naj
    Sep 6 '20 at 21:43
  • $\begingroup$ Any question is worth asking. That's how you learn, after all. But then again, some questions will be answered with a "yes", some with a "no", and some with "that's a wrong question to ask, because..." $\endgroup$ Sep 7 '20 at 5:32
  • $\begingroup$ And some questions will be answered clearly and helpfully (See @Maurice, below). $\endgroup$
    – Naj
    Sep 7 '20 at 6:27
  • $\begingroup$ Note that your teacher is using an outdated depiction of phosphate. It is better to rotate the bottom oxygen in the leftmost picture 90° clockwise before making a bond. The resulting bond is a single bond, not a double bond in keeping with calculation and experiment. $\endgroup$
    – Jan
    Sep 10 '20 at 11:14

Well ! A neutral substance like $\ce{PO4}$ does not exist. It only exists as an ion with three negative charges : $\ce{PO4^{3-}}$. These charges can come from three atoms of the first column like Hydrogen $\ce{H}$ or sodium $\ce{Na}$. These atoms become the cations $\ce{H^+}$ and $\ce{Na^+}$ after this electron "gift". So the ion phosphate is always surrounded by three ions like $\ce{H+}$ or $\ce{Na+}$. This is why the phosphate ions may be obtained by dissolving neutral substances like $\ce{Na3PO4}$ or $\ce{H3PO4}$ in water. They will never exist alone.


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