Which element in Period 4 is the most chemically active non-metal?

The crust of earth may a- continets and ocean floors. b-continents only. c-layers of sedimentary rocks and continents. d-all of the above

If a solution is considered basic, then a) the hydroxide ion and hydronium ion concentrations are equal. b) the hydroxide ion concentration is less than the hydronium ion concentration. c) the hydronium ion concentration is greater than the hydroxide ion concentration. d) the hydroxide ion concentration is greater than the hydronium ion concentration.

Which is true of a liquid? it has a definite volume but not a definite mass. it has a definite mass but not a definite volume. it has a definite volume but not a definite shape. it has a definite shape but not a definite volume.