Answer:
Since different isotopes of an element have different numbers of neutrons (but always the same number of protons) they have different mass numbers. Nitrogen-14 and nitrogen-15 are both stable isotopes of nitrogen. However, the other 5 isotopes are all unstable.
A) can enter from the surroundings, but cannot escape to the surroundings
As long as the chemical is not used up in the reaction the answer is true
Answer:
It depends on what kind and how much. Some are about $100, and others are $1,000.
gold is usually found in pure form because it is not reacting with other chemicals naturally.
