Which of these subatomic particles adds the most mass to an atom?
a. proton
b. photon
c. electron
d. it depends on what the element is.
an atom with two protons, three neutrons and two electrons would have a mass of about how many atomic mass units?
a. 2
b. 3
c. 5
d. 7

To prevent the presence of air, noble gases are placed over highly reactive chemicals to act as inert "blanketing" gases. a chemical engineer places a mixture of noble gases consisting of 4.37 g of he, 13.36 g of ne, and 36.65 g of kr in a piston-cylinder assembly at stp. calculate the partial pressure in torr of kr.