Question

an element x atomic no. 17 reacts with an element y atomic no. 20 to form a divalent halide .where in the periodic table are element x and y placed?identify nature of oxide and nature of bonding?

Answer 1

The element with atomic no. 17 is chlorine(Cl=2,8,7) and element with atomic no. 20 is calcium (Ca= 2,8,8,2)
Here, we see that, Ca is divalent by losing outermost electrons while Cl is monovalent as it requires only one electron. So, the halide formed is CaCl₂.
Chlorine is placed in group 17 in period 3 and Calcium is placed in group 2 in period 4.
The oxides of calcium are basic in nature and forms strong base hydroxide in water medium. While, oxides of Chlorine is acidic in nature.