Q.Lewis dot diagrams for the following:

A Lewis dot structure pictures a molecule's or ion's bonding purely in terms of shared electron pairs (bonds, usually drawn as dashes) and lone pairs (dots), built around the octet rule — every atom loses, gains or shares electrons until its outermost shell holds eight electrons (or two, a duplet, for H). It is drawn using a fixed procedure: first add up the total number of valence electrons contributed by all the atoms (adjusting up for a negative ionic charge or down for a positive one); sketch the skeletal connectivity, with the LEAST electronegative atom usually placed centrally (e.g. S is central in $\text{SO}_4^{2-}$, N in $\text{NO}_3^-$), and one single bond (shared pair) linking every pair of directly bonded atoms; complete every atom's octet as far as possible by adding lone pairs; and, if any atom's octet is STILL short after that, convert one or more single bonds into double or triple bonds until every atom's octet is satisfied. Where a species can be drawn in more than one valid way — differing only in which atom carries the multiple bond — formal charge (see the separate Formal Charge concept) is the tool used to judge which candidate structure best represents the real molecule. A Lewis structure remains a useful first picture of a molecule's connectivity and electron count, but on its own it says nothing about the molecule's actual three-dimensional shape (VSEPR theory is needed for that) and cannot always predict its true magnetic or energetic behaviour (e.g. it wrongly predicts O2 should be diamagnetic).