Oxygen has an atomic number of eight and atomic mass of 16 how many valance electrons does it have?

Compare and contrast refraction of light and sound will give brainliest

Draw the aromatic compound toluene (methylbenzene). show all hydrogen atoms, including those on the ring.

Which best describes the present-day universe? opaque, expanding very slowly, stars produce heavy elements transparent, expanding at an accelerated rate, stars produce heavy elements opaque, expanding at an accelerated rate, stars produce only hydrogen and helium transparent, expanding very slowly, stars produce only hydrogen and helium