Question

The position of three elements A, B and C in the
Periodic Table is shown below:
Group16 Group17
--- ---
--- A
--- ---
B C
give reasons explain the following-
a) element A is a non metal
b) element B has a large atomic size than element C.
c) elements C has a valency of 1
​

Answer 1

Answer:

(a) A belongs to group 17. There are 7 electrons in its valance shell. Therefore it tend to accept one electron to complete octet. Hence, it is a non-metal.

(b) C is less reactive than A. As both elements belong to same group and going down to group size of element increases. A is a smaller than C therefore the cloud of electron density surrounding the nucleus is more compact. The stability of completing the octet for A is greater than for C as A is more keen to obtain an electron than C.

(c) C is smaller than B. C and B belongs to same period. Atomic radius decreases from left to right within a period. This is caused by the increase in the number of protons and electrons across a period. One proton has a greater effect than one electron; thus, electrons are pulled towards the nucleus, resulting in a smaller radius.

(d) A will form anion A

−

. A belongs to group 17. There are 7 electrons in its valance shell. Therefore it tend to accept one electron to complete octet and forms anion