The periodic table is based on an element's a. atomic number. b. molecular size. c. molecular mass. d. atomic mass.

Nuclear fusion is the source of energy for stars. besides hydrogen, which other element is most likely also common in stars?

Which of the following did jj thompson discover about atoms? a)an atom has an internal structure. b) atoms are tiny indivisible particles. c)electrons orbit the nucleus of an atom. d) the nucleus of an atom contains protons and neutrons.

Which of the following is an example of physical change not a chemical change? a) a log gives off heat and light as it burns. b) a tree stores energy from the sun in its fruit. c) a penny lost in the grass slowly changes color. d) a water pipe freezes and cracks on a cold night.