(a) (i) All the elements of a group have similar chemical properties because they have same no. of valence electrons in their outermost shell. (ii) All the elements of a period have different chemical properties because they have different no. of valence electrons in their atoms.
The correct answer is: [B]: ___________________________________________________________ " N₂ (g) + 3 H₂ (g) → 2 NH₃ <span>(g) " . ___________________________________________________________ Note of interest: ___________________________________________________________ This particular reaction is known as the "</span>Haber process" . ___________________________________________________________
