How many electrons are found in a C and O2-, respectively?

Carbon has a total of six electrons and there are a total of ten electrons in the oxygen ion.

What we can easily find in common with carbon and oxygen atom is the fact that the both of them have two shells. We can also refer to these shells as energy levels.

In both atoms, the first shell contains only two electrons. For carbon, the second shell contains four electrons while the second shell of oxygen ion contains eight electrons.

Hence, Oxygen ion has two electrons in the first shell and eight electrons in the second shell(total of ten electrons) while carbon has two electrons in the first shell and four electrons in the second shell (a total of six electrons).

The electronic configuration of carbon is: 1s2, 2s2, 2p2

The electronic configuration of oxygen ion  is: 1s2, 2s2, 2p6

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c-14 is carbon-14, or radiocarbon.   it is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons.

colorless gas, exhibiting a blue glow when placed in an electric field

b) solid

its a type of rock