What is the measurement 111.009 mm rounded off to four significant digits? a. 111 mm b. 111.0 mm c. 111.01 mm d. 110 mm select the best answer from the choices provided

the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.