Which diagram shows the correct number of valence electrons for a carbon atom?

The right answer is C.

In the ground state, carbon only shows two single electrons. Its tetravalence is explained by the fact that the carbon redistributes two electrons on its L layer, allowing to have four connecting electrons. Raising an electron on a higher electron orbital is called the excitation of an atom.

Methane (CH4) is archetypal of carbon compounds: the tetravalent carbon atom forms four simple covalent bonds with four hydrogen atoms. The carbon atom is called tetravalent because it can establish up to four different single bonds with other atoms or establish, as in the case of alkenes, two single bonds and a double bond, or as in the case of alkynes , a single bond and a triple bond.

1. amino acid refers to the fundamental building block of proteins, comprising of an amino group and a carboxyl group.

2. catalyst refers to any substance, which increases the rate of chemical reaction without being used up in the reaction.

3. a complex molecule containing he genetic code is dna or deoxyribonucleic acid.

4. an enzyme refers to a molecule of protein, which is unique in accelerating up a particular chemical reaction in the biological systems.

5. nucleic acid refers to an sequence of sugars, phosphates, and nitrogenous bases, for example, dna and rna.

6. a protein refers to a large, composite organic molecule comprising of a huge number of amino acids associated together with the of peptide bonds.

7. rna refers to a nucleic acid that takes part in the production of proteins.

8. substrate refers to a compound, which takes part in a chemical reaction, and is chemically modified by the reaction.