Express the results of this calculation to the correct number of significant figures: 1.02 - 0.0421 0.98 0.978 0.9779 1 plzzz

You may expect bonds between two atoms which each have n covalent lonic metallic hydrogen

1) in saturated limewater, [h+ ]=3.98x10-13 m. a) find [oh]-/ b) what is the ph? / c) is the solution acidic, basic, or neutral? / 2) in butter, [h+ ]=6.0x10-7 m. a) find [oh]-/ b) what is the ph? / c) is the solution acidic, basic, or neutral? / 3) in peaches, [oh]=3.16x10-11 m a) find [h+ ]/ b) what is the ph? / c) is the solution acidic, basic, or neutral? / 4) during the course of the day, human saliva varies between being acidic and basic. if [oh]=3.16x10-8 m, a) find [h+ ]/ b) what is the ph? / c) is the solution acidic, basic, or neutral? /

An atom of sodium-23 (atomic number = 11) has a positive charge of +1. give this information, how many electrons does it have? how many proteins and neutrons does this atom have