Question

The position of three elements A, B and C in the periodic table is shown below,

Group 16	Group 17
-	-
-	A
-	-
B	C

A.State whether A is a metal or nonmetal
B.State whether C is more reactive or less reactive than A.
C.Will C be larger or smaller in size than B?
D.Which type of ion, cation or anion, will be formed by element A?

Answer 1

Hint: We have to know the position and properties of various elements in the periodic table. We can tell that group-16 belongs to the oxygen family and group 17belongs to the halogen family.

Complete step by step answer:
From the periodic table, we can see that group -17 consists of the halogen family and group-16 elements belong to the oxygen family.
We know that group-17 elements are the halogens. The number of electrons present in the outermost orbital is seven; therefore it has the capacity to accept one electron to form an octet. From that, we can conclude that A is a non-metal.
We can see A and C belongs to the same group that is the halogen family. On moving down the group, the sizes of the element increase. The size of A is smaller than C, hence the electron cloud density surrounding the nucleus is more compact. The stability of attaining the octet for A is higher than for C as A would obtain an electron faster than C. Hence, C is less reactive than A.
The size of C is smaller than B because the atomic radius decreases from left to right within a period. In the given table, we can see C and B are in the same period. There is an increase in the number of protons and electrons across a period. The effect of the proton is greater than that of the electron, and it is easily pulled towards the nucleus, thereby resulting in a smaller radius.
The element A will form an anion A-. All the elements of group 17 have 7 electrons in their outermost shell and thus, they accept one electron to attain the octet to form anions.

Note:
We know that both Group-16 and group-17 are non-metals, but group-17 is the most reactive group in the periodic table because they have high electronegativity value, and can easily accept an electron from other elements.