Who wants to talk i have been bored all day BTW I am a 14 year old girl

Elements in group 2 are all called alkaline earth metals. what is most similar about the alkaline earth metals?

A0.10 m aqueous solution of sodium sulfate is a better conductor of electricity than a 0.10 m aqueous solution of sodium chloride. which of the following best explains this observation? (a) sodium sulfate is more soluble in water than sodium chloride. (b) sodium sulfate has a higher molar mass than sodium chloride. (c) to prepare a given volume of 0.10 m solution, the mass of sodium sulfate needed is more than twice the mass of sodium chloride needed. (d) more moles of ions are present in a given volume of 0.10 m sodium sulfate than in the same volume of 0.10 m sodium chloride. (e) the degree of dissociation of sodium sulfate in solution is significantly greater than that of sodium chloride.

How many significant figures are in the following numbers ? a. 0.0002030 b. 2.000 c. 2.008900 d. 145.00