Metals generally melt at very high temperatures. Amongst the following,the metal with the highest melting point will be $......$

Which of the following is the reason why sodium metal conducts electricity?

The alkali metal halides are soluble in water but $LiF$ is insoluble because

Which element from the following is used in photoelectric cells?

$A$ 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 $Y$?

The magnetic behaviour of $Li_2O$,$Na_2O_2$ and $KO_2$,respectively,are