Question
Give the atomic number and electronic configuration of the following elements:
(i) The third alkali metal
(ii) The second transition element
(iii) The fourth noble gas
(iv) The first halogen.
Solution
(i) The third alkali metal :The atomic number is 19 and the electronic configuration is, 1s2 2s2 2p6 3s2 3p6 4s1.
(ii) The second transition element: The atomic number is 22 and the electronic configuration is, 1s2 2s2 2p6 3s2 3p6 4s2 3d2.
(iii) The fourth noble gas: The atomic number is 36 and electronic configuration is, 1s22s2 2p6 3s2 3p6 4s2 3d10 4p6.
(iv) The first halogen: The atomic number is 9 and electronic configuration is, 1s2 2s22p5.
