Atomic physicists do not know why all of the atomic particles stay together within an atom

1) sections 1, 2, and 10 are significant primarily because they suggest the likelihood that a) widow wycherly is actually the woman in the full-length portrait. b) dr. heidegger wants to include his guests in an experiment with the water. c) dr. heidegger plans to drink some of the water from the vase and needs witnesses. d) the guests will be asked to witness dr. heidegger's transformation when he drinks the water.

Achlorine atom has 17 protons and 18 neutrons. what is its mass number? what is its atomic number?

If you put a helium-filled balloon in the refrigerator, what will happen?