The atomic numbers of three elements A, B and C are given below :
Element Atomic number
A 5
B 7
C 10
(i) Which element belongs to group 18? (ii) Which element belongs to group 15?
(iii) Which element belongs to group 13? (iv) To which, period/periods do these elements belong?
An element belongs to the 3rd period and Group IIIA (13) of the periodic table.State:
(a) the number of valence electrons,
(b) the valency,
(c) if it is a metal or non-metal ?
(d) the name of the element.