16.
Which of the following elements is a metalloid?
a. As
c. Br
b. Se
d. Kr

13. a covalent bond between two atoms is likely to be polar if: a. one of the atoms is much more electronegative than the other. b. the two atoms are equally electronegative. c. the two atoms are of the same element. d. the bond is part of a tetrahedrally shaped molecule. e. one atom is an anion.

Fossil fuels are organic compounds that are made from

How does kepler second law of planetary motion overthrow one of the basic beliefs of classical astronomy