Question

isotopes
the number of in a nucleus determines the identity of the element. for example, any atom having 6 protons will be a 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 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 isotopes 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 symbol signify? ex. carbon - 12
3. how can you tell isotopes of the same element apart?

part ii. for each of the following isotopes, write the number of protons, neutrons, and electrons. assume all atoms are neutral.

	chromium - 58	chromium - 63

|# of protons|
|# of neutrons|
|# of electrons|
|mass|

	carbon - 12	carbon - 13	carbon - 14

|# of protons|
|# of neutrons|
|# of electrons|
|mass|

Explanation:

1. An isotope is an atom of an element with the same number of protons but a different number of neutrons, resulting in the same atomic number but a different atomic mass.
2. The number next to an isotope symbol (e.g., in Carbon - 12) is the mass number, which is the sum of protons and neutrons in the nucleus.
3. Isotopes of the same element can be told apart by their mass numbers, which are different due to the different number of neutrons while the number of protons remains the same. For the table part:

• Chromium has an atomic number of 24. For Chromium - 58: Protons = 24 (from atomic number), Neutrons = 58 - 24 = 34, Electrons = 24 (since neutral), Mass = 58. For Chromium - 63: Protons = 24, Neutrons = 63 - 24 = 39, Electrons = 24, Mass = 63.
• Carbon has an atomic number of 6. For Carbon - 12: Protons = 6, Neutrons = 12 - 6 = 6, Electrons = 6, Mass = 12. For Carbon - 13: Protons = 6, Neutrons = 13 - 6 = 7, Electrons = 6, Mass = 13. For Carbon - 14: Protons = 6, Neutrons = 14 - 6 = 8, Electrons = 6, Mass = 14.

Answer:

1. An atom of an element with the same number of protons but a different number of neutrons, having the same atomic number but a different atomic mass.
2. The mass number, which is the sum of protons and neutrons in the nucleus.
3. By their mass numbers.

	Chromium - 58	Chromium - 63
# of neutrons	34	39
# of electrons	24	24
Mass	58	63
	Carbon - 12	Carbon - 13	Carbon - 14
# of protons	6	6	6
# of neutrons	6	7	8
# of electrons	6	6	6
Mass	12	13	14