Question

isotopes
the number of protons in a nucleus determines the identity of the element. for example, any atom having 6 protons will be a \carbon\ atom. if we were to add an extra proton to the nucleus, we would have an entirely different element. for example,
c (6 protons) + 1 proton → n (7 protons)
on the other; hand, if we add an extra neutron to a nucleus we simply end up with the same element, just a little heavier, since the charge on the nucleus would be unchanged.
isotopes of a given element have the same atomic number but a different atomic mass.
in other words, isotopes have the same number of protons but a different number of neutrons. an isotope is identified by its mass number, the sum of the protons and neutrons. the most common isotope of carbon has a mass number of 12 and can be written as carbon - 12, two other isotopes are carbon - 13 and carbon - 14. despite their different mass numbers, all three carbon isotop react the same way chemically.
part i. answer the questions based on the above reading.

1. what is an isotope?
2. what does the number next to isotopes signify?
3. how can you tell isotopes of the same element apart?

Explanation:

1. Isotopes are defined in the text as having the same atomic number (same number of protons) but different atomic mass (different number of neutrons).
2. The number next to isotopes is the mass number, which is the sum of protons and neutrons.
3. Isotopes of the same element can be told apart by their different mass numbers.

Answer:

1. Isotopes of a given element have the same atomic number but a different atomic mass, meaning they have the same number of protons but a different number of neutrons.
2. The number next to isotopes signifies the mass number, which is the sum of the protons and neutrons in the isotope.
3. You can tell isotopes of the same element apart by their different atomic masses or mass numbers.