39. The positions of three elements A, B and C in the periodic table are shown below:
Group 16
Group 17
A
B
C С
(a) State whether A is a metal or non-metal.
(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 by element A?
Answers
Explanation:
(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.