Observation and assessment are most effective when a. tools are appropriate for the children in your setting and meet professional requirements for quality. b. the state has selected them as an appropriate tool for you to use. c. parents select the tools you use. d. assessments are formal and gather focused information.

c is having 4 valence electrons and is bonded to three hydrogens and one sulphur atom, therefore, the number of bond pair is equal to four. as all the valence electrons are used in forming the bonds so, there is no lone pair left on carbon.

s is having 6 valence electrons and is bonded to one other sulfur atom and one carbon atom, therefore, the number of bond pair is equal to 2. as only two valence electrons are used in forming the bonds so, four electrons are left. therefore, two lone pairs are present on s.