1. Tardigrade
  2. Question
  3. Chemistry
  4. The first (IE1) and second (IE2) ionization energies (kJ/mol) of a few elements designated by Roman numerals are given below. Which of these would be an alkali metal? IE1 IE2 (a) I 2372 5251 (b) II 520 7300 (c) III 900 1760 (d) IV 1680 3380

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Q. The first $(IE_1)$ and second $(IE_2)$ ionization energies (kJ/mol) of a few elements designated by Roman numerals are given below. Which of these would be an alkali metal?
$IE_1$ $IE_2$
(a) $I$ 2372 5251
(b) $II$ 520 7300
(c) $III$ 900 1760
(d) $IV$ 1680 3380

Classification of Elements and Periodicity in Properties

Solution:

As alkali metals have the lowest $IE_1$ values in their respective periods and also there is a large jump between $IE_1$ and $IE_2$ due to the removal of second electron from the noble gas core, therefore, out of the given $IE_1$ and $IE_2$ values, $(II)$ belongs to alkali metals.