The position of certain elements in the Modem Periodic Table are shown below:
Using the above table answer the following questions giving reasons in each case:
(i) Which element will form only covalent compounds?
(ii) Which element is a non-metal with valency 2?
(iii) Which element is a metal with valency 2?
(iv) Out of H, C and F which has largest atomic size?
(v) To which family does H, C and F belong?
Answer
(i)
Element E (silicon) belongs to group 14 and period 3.
Electronic configuration of E: 2, 8, 4
Number of Valence electrons = 4
Since it has 4 electrons in its outermost shell , it can neither gain electrons nor lose electrons as it will become unstable.
So, it forms covalent bonds (by sharing electrons).
(ii)
Electronic configuration of B: 2, 8, 6
Number of valence electrons = 6
Valency = 2
Since, B has valency 2, it gains 2 electrons to become stable.
Metals lose electrons to become stable whereas, non-metals gain electrons to become stable.
So, element B(oxygen) is a non-metal with valency 2.
(iii)
Electronic configuration of D: 2, 8, 2
Number of valence electrons = 2
Valency = 2
Since, D has valency 2, it will lose 2 electrons to become stable.
Metals lose electrons to become stable whereas, non-metals gain electrons to become stable.
So, element D(magnesium) is a metal with valency 2.
(iv)
H, C and F all belong to the same group. Element F comes below C and H.
So, element F(argon) has the largest atomic size .
(v)
H, C and F belong to group 18 which means their octet is complete and these elements are stable.
Elements with filled octet belong to the noble gas family.
