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) Place the three elements: Fluorine, Beryllium and nitrogen in the order of increasing electronegativity.
(d) Which one of the above element belongs to the halogen series?
Answers:
(a) Li, Be, B, C, O, F, Ne belongs to 2nd period.
(b) The missing element is Nitrogen (N) and it must be placed between C and O.
(c) Be< N< F
(d) The element Fluorine belongs to the halogen series.