Question

The elements of one short period of the periodic table are given below in order from left to right: Li Be B C O F Ne
(a) To which period do these elements belong?
(b) One element of this period is missing. Which is the missing element and where should it be placed?
(c) Which one of the elements in this period shows the property of catenation?
(d) Place the three elements, fluorine, beryllium and nitrogen, in the order of increasing electronegativity.
(e) Which one of the above elements belong to the halogen series?

Answer 1

(a) These elements belong to the second period.
(b) Missing element is nitrogen (N). It should be placed between carbon (C) and oxygen (O).
(c) Carbon (C) shows the property of catenation.
(d) The increasing order of electronegativity in flourine, beryllium and nitrogen is: Be < N < F
(e) Fluorine (F) belongs to the halogen series.