Final answer:
The given electron configurations represent two different elements, with statement C being true. Statement B is also true because (i) represents sodium. Energy is required to change from (i) to (ii), making statement A true. However, statement D is false because (i) requires less energy to remove an electron compared to (ii).
Step-by-step explanation:
The given electron configurations represent two different elements: (i) 1s²2s²2p³3s¹ and (ii) 1s²2s²2p⁶3s¹. So, statement C is true. The electron configuration (i) represents the element sodium (Na). Therefore, statement B is true. Energy is required to change the electron configuration from (i) to (ii) by removing one electron from (i). So, statement A is true. More energy is required to remove one electron from (i) than from (ii) because (i) has a partially filled 3s orbital, which is closer to the nucleus compared to the 4s orbital in (ii). Hence, statement D is false.