Consider the electronic configurations : (i) `1^(2) 2s^(1)` (ii) `1s^(2) 3s^(1)`
(a) Name the element corresponding to (i)
(b) Does (ii) correspond to the same or different element ?
(c) How can (ii) be obtained from (i) ?
(d) Is it easier to remove one electron from (ii) or (i) ? Explain.

Explanation

(a) The element corresponding to (i) is Lithium (Li). (b) This electronic configuration represents the same element in the excited state. (c) By supplying energy to the element when the electron jumps from the lower energy 2s-orbital to the higher energy 3s-orbital.
(d) It is easier to remove an electron from (ii) than from (i) since inthe former case, the electron is present in a 3s-orbital which is away from the nucleus and hence is less strongly attracted by the nucleus than an electron in the 2s-orbital.