The number of electrons in the valence shell of calcium is

All of the following substances react with water. Which of the following pairs will produce the same gaseous product upon reaction with water?

Which of the following elements has the highest tendency to form a peroxide?

All the elements of group $2$ react with water to form metal hydroxide and hydrogen,except the element

Identify the option in which the trends corresponding to hydroxides of group $2$ elements (from $Mg(OH)_2$ to $Ba(OH)_2$) are correctly shown:

Basic character

Chemical stability

Solubility

Which of the following produces hydrolith with dihydrogen?