In an ionic compound moles ratio of cation to anion is `1:2`. If atomic masses of metal and non-metal respectively are `138` and `19`, then correct statement is

The atomic number of an element is 19.Is the element a metal or non-metal?

Which of the following statement is/are incorrect in the rock-salt structure if an ionic compounds ? (A) coordination number of cation is four where as that of anion is six. (B) coordination number of cation is six where as that of anion is four. (C) coordination number of each cation and anion is four. (D) coordination number of each cation and anion is six.

The atomic numbers of the metallic and non-metallic elements which are liquid at room temperature respectively are:

The atomic numbers of the metallic and non-metallic elements which are liquid at room temperature respectively are:

The atomic numbers of the metallic and non-metallic elements which are liquid at room temperature respectively are: