Three are three elements `X,Y` and `Z` having atomiv numbers of 6,16 and 19 respectively. Based on this information, Rakshit has been asked to answer the following questions:
(a) In which group of the periodic table would you expect to find (i) element `X` (ii) element `Y` and (iii)( element `Z`?
(b) Which two elements will form ionic bonds ? Why?
(c) What will be the formula of ionic compound formed ?
(d) Which two elements will form covalent bonds? Why?
(e) What will be the formula of covalent compound formed?
(f) What values are displayed by Rakshit in answering the above questions?

Explanation

In order to answer the questions Rakshit first wrote down the electronic configurations of the element `X,Y` and `Z` by using their atomic numbers as follows:

(a) (i) Element `X` has 4 valence electrons in its atom, so it will occur in group `4+10=14` of the modern periodic table.
(ii) Element `Y` has 6 valence electrons in its atom, so it will be found in group `6+10=16` of the modern periodic table.
(iii) Element `Z` has just 1 valence electron in its atom, so it will be in group 1 of the modern periodic table.
(b) An ionic bond is formed between a metal element and a non-metal element. Now, element `Z` of group 1 is a metal and element `Y` of group 16 is a non-metal, therefore, the elements `Z` and `Y` will combine to form ionic bonds (Please note that element `X` of group 14 is also a non-metal carbon but it does not combine with metals to form ionic bonds).
(c) The element `Z` has 1 valence electron, so its valency is 1 (or 1+). Element `Y` has 6 valence electron so its valency will be 2 (or `2-`). Here two `Z^(+)` ions will combine with one `Y^(2-)` ion so that the formula of ionic compound formed will be `Z_(2)Y`.
(d) A covalent bond is formed between two non-metal elements. Here, element `X` of group 14 a non-metal and element `Y` of group 16 is also a non-metal therefore, the elements `X` and `Y` will combine together to form covalent bonds.
(e) The element `X` has 4 valence electrons, so its valency is 4. The element `Y` has 6 valence electrons so its valency is 2. This means that one atom of element `X` will combined with two atoms of element `Y` to form a covalent compound having he formula `XY_(2)`.
(f) The values displayed by Rakshit in answering these questions are (i) Knowledge of modern classification of elements (ii) Understanding of periodic table and chemical bonding and (iii) Problem solving skills.