Final answer:
The maximum number of electrons that carbon's outer shell can hold is eight. Carbon has four valence electrons naturally, but it can bond with other atoms to reach the stable octet configuration with eight electrons in its outer shell. The second energy level, where the valence electrons are, includes s and p orbitals, accommodating up to eight electrons when all are filled.
Step-by-step explanation:
The maximum number of electrons that carbon's outer shell can hold is eight. This corresponds to the full capacity of its second energy level, which is also known as the valence shell for carbon. Carbon, with an atomic number of 6, has two electrons in its first energy level (1s orbital) and four electrons in its second energy level (2s and 2p orbitals). According to the octet rule, atoms are most stable when their valence shell is filled with eight electrons. While carbon naturally has four valence electrons, through bonding, it can achieve a stable configuration with eight electrons in its outer shell.
For instance, two carbon atoms combined can share valence electrons to form a stable molecule. When considering their electron configurations, two C atoms have a total of 2 x 4 = 8 valence electrons, and if they are combined with four hydrogen atoms (each contributing one electron), they will have a total of 12 valence electrons in the molecule. These electrons are shared among the atoms to fill their outer shells, following the octet rule.
Furthermore, the structure of the 2p orbital allows each p orbital to hold up to two electrons, and there are three p orbitals in the second energy level, which gives a total of six possible electrons in the p orbitals. This, coupled with the two electrons that can fill the 2s orbital, leads to the maximum of eight electrons that can be accommodated in the second energy level of carbon.