9701 MCQ Solution 3

Question 3: [Physical > Atomic Structure]

Use of the Data Booklet is relevant to this question.

In the gas phase, aluminium and a transition element require the same amount of energy to form one mole of an ion with a 2+ charge.

What is the transition element?

A Co

B Cr

C Cu

D Ni

Reference: Past Exam Paper – November 2002 Paper 1 Q3

Solution 3:

Answer: A.

For aluminium to form an ion with a 2+ charge we must add its 1^st ionisation energy, to remove one electron and gain 1 positive charge, with its 2^nd ionisation energy, to remove another electron from the 1+ aluminium ion to make it a 2+ ion. This total energy, according to the data booklet, is 577 + 1820 = 2397. Thus we have to find a transition element that has the same total energy required for removing 2 electrons.

A Co: 757 + 1640 = 2397

B Cr: 653 + 1590 = 2243

C Cu: 745 + 1960 = 2705

D Ni: 736 + 1750 = 2486

As you can see Co is the only exact match thus is the A is the correct answer.