5. Replicate water samples are analyzed for water hardness with the following results: 102.2, 102.8, 103.1 and 102.5ppm CaCO3. Calculate:-
(a) The standard deviation
(b) The relative standard deviation
(c) The standard deviation of the mean
(d) The relative standard deviation of the mean.​

the number of protons in the nucleus of a given element. has slight luster and conducts electricity at high temperatures like metal.but like a nonmetal,boron is brittle and does not conduct electricity well at low temperatures. in graphite, carbon is a soft,brittle solid.it is reflective,ductile,or malleable.