Question

Which of the following is not true about transuranium elements?

(a) Atomic number > 92

(b) Elements after Uranium

(c) Decay radioactively as they are unstable

(d) Example is Thorium

I have been asked this question in exam.

This is a very interesting question from Electronic Configurations and Types of Elements: s, p, d and f Blocks in portion Classification of Elements and Periodicity in Properties of Chemistry – Class 11

Answer 1

Correct answer is (d) Example is Thorium

The explanation: The elements after Uranium (Z = 92) are known as transuranium elements, they are unstable and decay radioactively into other elements. But the atomic number of Thorium is 90, hence it is not a transuranium element.