WHY is 4 the maximum number of bonds a carbon atom can form with other atoms and non-carbon atoms?

Question

there always has to be a why.....

Answer 1

Carbon has a total of 6 e- and only 4 of them are in the valence level. The difference in energy between the inner e- and valence e- is too great for a C atom to move the inner e- to a valence level. Since there are only 4 valence e- C can only bond 4 times at the most.

Answer 2

The answered can be dealt with quantum numbers. Carbon is in the second energy level, so n=2. This can be calculated by looking at the periodic table and noticing that Carbon falls on the second row. This number is also called the shell. The next number that we can calculate is the sub-shell ("L"), or the angular momentum quantum number. L can have values of n-1. So the values of L are 1 and 0. 0 is the S-subshell and 1 is the P subshell. So in this case, carbon only has an outermost s and p sub-shells. You can only fit 2 electrons in the s-subshell and 6 in the p-subshell. So the highest number of bonding electrons that carbon can have is 8.

Only atoms that fall in the n=3 and higher can have an "expanded octect" in other words it can have more than 4 bonds. Also, when carbon forms 4 bonds, it has a formal charge of 0, which is very stable. Any other number of bonds will result in a formal charge that is not zero, and thus would be unstable.

Answer 3

Six is the maximum coordination number of isolated carbon compounds. Carbon's highest coordination number might be eight.

CH5(+) and CH6(2+) have been made and observed in superacids. Isolable carbide-containing clusters can have five ligands on carbon, Fe5C(CO)15; six ligands on carbon, Ru6C(CO17). The maximum number of bonds to carbon in a stable, isolable compound is then at least six.

http://adsabs.harvard.edu/abs/1999JChEd..76..201B

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Answer 4

because of the number of valence electrons in its outer shell. there are 6 protons (and therefore usually 6 electrons) in a carbon atom, meaning that two electrons are in its first shell and four are in its second shell. there is a maximum number of electrons each shell can hold, the first can hold 2, and the second shell can hold 8. since four are already therein the second shell, there are only four "vacant spots"

i believe this is correct. this is a very basic answer from my very basic knowledge of atoms. hope it helps.

Answer 5

Quantum number!