The bohr nuclear model suggests that: electrons have a positive charge. most of the atom is made of empty space. the nucleus is made of neutrons and electrons. the mass of an atom equals the number of protons.

Which of the following pairs of elements belong to the same groupa. h and he b. li and bec. c and pb d. ga and ge

Calculate the molar mass of aluminum oxide (al2o3). express your answer to four significant figures.

Why is soap used to remove grease? a. its nonpolar end dissolves the grease. b. it makes the water bond with the grease. c. it chemically bonds with the grease. d. its polar end dissolves the grease.correct answer for apex - a, its nonpolar end dissolves the grease.