4 When a reaction produces a gas, the gas is released into the environment. If you want to be able to support conservation of mass, how could you be sure to include the mass of the gas produced?

radioactive decay occurs in unstable atomic nuclei – that is, ones that don't have enough binding energy to hold

the nucleus together due to an excess of either protons or neutrons.

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.

how important do you think an instrument is to the musician who plays it?