The electron configuration of carbon atom in its excited state is [ 6C]

The electron configuration of an atom describes the arrangement of electrons in its energy levels or orbitals. The notation [ 6C ] means that the excited carbon atom has six electrons in its outermost energy level, which is the second energy level (n=2). The correct electron configuration for a carbon atom in its excited state is 1s²2s¹2p². The notation [ 6C ] can be understood as follows: the normal electron configuration for carbon is 1s²2s²2p², meaning that it has four electrons in its outermost energy level. By exciting one of the 2s electrons to the empty 2p orbital, the atom now has a total of six electrons in the n=2 energy level, hence the notation [ 6C ]. Option D, 1s²2s¹2px¹2py¹2pz¹, represents the electron configuration of a carbon atom in its ground state.