* Valence electrons are associated with individual atoms. They are the electrons in the outermost shell of an atom, and they are the ones involved in chemical bonding.
* Compounds are formed by sharing or transferring electrons. In calcium carbonate, calcium (Ca) loses two electrons, carbon (C) shares four electrons, and oxygen (O) shares two electrons to form the compound.
To understand the bonding, you need to consider the individual atoms:
* Calcium (Ca): Has 2 valence electrons.
* Carbon (C): Has 4 valence electrons.
* Oxygen (O): Has 6 valence electrons.
Therefore, it's not appropriate to talk about the "valence electrons" of the entire calcium carbonate molecule. Instead, we focus on the individual atoms and how their valence electrons participate in forming the bonds that hold the molecule together.
