Question

A radioactive isotope of radium placed in the second group in the periodic table emits one $\alpha$-particle and one $\beta$-particle. The new element formed is in the ________ group.

• A. first
• B. second
• C. third
• D. fourth

Answer 1

The correct option is A first

If the particle emits one $\alpha$particle so its atomic number decreases by 2. After emitting $\beta$particle the atomic number of new element increases by 1. So, Net decrease is 1 so new element is predecessor of original element. So, it must lie in first group.