Correct statement/s among the following with respect to ionization energy (IE) is/are (i) (IE₁ + IE₂ + IE₃)… · ABC26IN0211
Subject: Inorganic Chemistry · Chapter: Main Group Elements · Topic: Main Group Elements – General · Exam: CSIR NET 2020 · Marks: 2 · Difficulty: Medium
Correct statement/s among the following with respect to ionization energy (IE) is/are (i) ($\mathrm{IE_1 + IE_2 + IE_3}$) for indium is more than that of aluminium (ii) $\mathrm{IE_1}$ of scandium is higher than that of cobalt (iii) $\mathrm{IE_1}$ of gallium is lower than that of selenium (iv) $\mathrm{IE_1}$ of nitrogen is greater than that of oxygen
(a)(ii) and (iv)
(b)(iii) and (iv)
(c)(i) and (iv)
(d)(ii) and (iii)
Answer
Answer (as printed): B
Explanation
•On moving down in a group, the atomic radius generally increases. Even though d-orbital is present in Indium, its size is greater than that of aluminium as electron is added to 5s orbital which has much higher size than that of 3s orbital of aluminium. Even after contraction, size of 5s orbital is greater than that of 3s orbital. Due to higher atomic radius of In, its outer electrons experience lesser attraction towards nucleus hence, (IE1 + IE2 + IE3) for In is less than that of Al. •On moving along the period, size decreases thus, effective nclear charge increases and hence I.E. increases. Therefore, IE1 of Co is higher than that of Sc and IE1 of Se is higher than that of Ga • Nitrogen has stable half-filled 2s2 2p3 configuration thus, has higher IE1 than that of oxygen.
Explanation as extracted from the printed page; notation may be imperfect.