Is h2o a polar or non polar compound?

Once similarity and one difference between a mixture of elements and a mixture of compounds

On the periodic table, elements are arranged by which of the following. a. mass numbers. b. increasing atomic number. c. alphabetical order. or d. density

Which statement is true regarding the diagram of circle p? the sum of y and z must be 2x. the sum of y and z must be x. the difference of z and y must be 2x. the difference of z and y must be x