Write the electronic configurations of the following ions: (a) H⁻ (b) Na⁺ (c) O²⁻ (d) F⁻. What are the atomic numbers of elements whose outermost electrons are represented by (a) 3s¹ (b) 2p³ and (c) 3d¹?

(i) (a) The electronic configuration of H⁻ is 1s². (b) The electronic configuration of Na⁺ is 1s²2s²2p⁶. (c) The electronic configuration of O²⁻ is 1s²2s²2p⁶. (d) The electronic configuration of F⁻ is 1s²2s²2p⁶. (ii) The atomic numbers of elements whose outermost electrons are represented by (a) 3s¹ (b) 2p³ and (c) 3d¹ are 11 (Na), 7 (N) and 21 (Sc) respectively. (iii) The following configurations indicate (a) [He]2s¹ (b) [Ne]3s²3p³ (c) [Ar]4s²3d¹ (a) Li (Z=3), (b) P (Z=15) and (c) Sc (Z=21) respectively.