Carbon differs markedly from the other members of group IV mainly because it
- A. is small, has no available d orbitals and forms strong multiple bonds with itself
- B. has a much larger atomic radius
- C. is a metal
- D. has a full outer shell
Explanation
Its small size lets carbon form stable double and triple bonds and catenate into long chains, which is the basis of the whole of organic chemistry, while the absence of d orbitals limits it to a maximum covalency of four. Silicon and the heavier members can expand their octets using d orbitals, so silicon forms SiF6 2- while carbon cannot form the analogous ion. Carbon has four outer electrons, not a full shell.