Which element has three electron shells and 4 valence electrons? Silicon

Carbon

Gallium

Argon

Silicon

Explanation:

For something to have 4 valence electrons, it must be in the 14th column, which elimates gallium and argon for the possible answers. For somethign to have 3 electron shells, it must be in the third row of the periodic table which means the answer is silicon.

Gallium

Explanation:

I believe this is the answer if not then the only other option is boron but anyways the answer is Gallium

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