This is forbidden because carbon does not have the space in its orbitals to accommodate ten electrons. Certain elements commonly encountered in organic chemistry may have ten valance electrons. These elements are in periods three and higher in the periodic table, and include chlorine, bromide, iodine, phosphorus and silicon. Of all the atoms commonly encountered in organic chemistry, only sulfur can routinely expand its octet to include twelve valence electrons. These atoms expand their octets so as to improve the importance of the resonance structure .
G is acceptable.
Structure H is not acceptable because the carbon has ten valance electrons. Structures I and J are both acceptable resonance contributors for bisulfate ion, the conjugate base of sulfuric acid. The sulfur atom of structure J has 12 valence electrons, an expanded octet. Sulfur is a third row element, so an expanded octet is allowed. Structure J is the more important resonance structure because it maximizes the number of covalent bonds and minimizes the number atoms with a nonzero formal charge.