The atomic numbers of four elements A, B, C and D are 6, 8, 10 and 12 respectively. The two elements which can react to form ionic bonds (or ionic compound) are:

46 The atomic number of an element X is 19. The number of electrons in its ion X⁺ will be: 47 The atomic number of an element Y is 17. The number of electrons in its ion y^- will be : 49 The atomic numbers of four elements P, Q, R and S are 6, 10, 12 and 17 respectively. Which two elements can combine to form a covalent compound ? 50 The solution of one of the following compounds will not conduct electricity. This compound is: