The radioactive element present in first group of s-block is _______.

Q. 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.

Q. A radioactive element is present in VIII group of the periodic table. If it emits one $\alpha$-particle, the new position of the nuclide will be:

Q. Assertion :The last element in a group is radioactive. Reason: In case of elements with high atomic masses, nucleus is unstable.

Q. A block having $12g$ of element is placed in a room. This element is a radioactive element with half-life of $15$ years. After how many years will there be just $1.5g$ of the element in the box?

Q. The outer electronic configuration of radioactive element present in IA group is :