Which of the following is Indian saltpetre?

Select the incorrect statement.

The element having electronic configuration $[Kr]4d^{10} 4f^{14} 5s^2 5p^6 6s^2$ belongs to

Identify the compound which gives $CO_2$ more readily on heating.

$A$ metal $X$ on heating in a stream of nitrogen gives $Y$. $Y$ on reaction with ${H_2}O$ gives a colorless gas which,when passed through a $CuSO_4$ solution,gives a blue color. What is $Y$?

How does the ionization energy of Group $1$ elements change down the group?