Answer:
compound, but I could be wrong
Approximately 99 because there is the same amount of electrons and the only things that go into the nucleus is protons and neutrons.
The Lewis structure the student drew is incorrect. The total number of electrons in bonds and lone pairs is equal to the total number of valence electrons available, then a valid Lewis structure is produced.
The correct structure is the following:
The structure that was drawn by the student was incorrect because the total number of electrons around Oxygen were incorrect, there were 6 instead of 8, which was against the octet rule. The correct structure should have 8 electrons around each atom.