Because they are chemically combined
Answer:
Here's where orbital hybridization came into play. According to this theory, when the carbon atom is in an excited state, one of the two electrons located in the 2s orbital will get promoted to the empty 2pz orbital. As a result, carbon now has 4 unpaired valence electrons with which it can form four bonds.
Explanation:
Valance electron are called
<span>The energy in coal comes from energy that was
stored in giant plants that lived hundreds of millions of years ago in
swamp forests, even before the dinosaurs! When these giant plants and
ferns died, they formed layers at the bottom of the swamps. Water and dirt began to pile up on top of the dead plant remains.</span>
Botanist is the type of scientist that studies materials found in plants