Here's why:
* Atomic Number: This represents the number of protons in an atom's nucleus. It defines the element. For example, all carbon atoms have 6 protons.
* Mass Number: This represents the total number of protons and neutrons in an atom's nucleus. Neutrons also contribute to the mass of an atom.
Isotopes have the same number of protons (atomic number) but different numbers of neutrons. This means they are the same element but have different masses.
Example:
* Carbon-12: 6 protons and 6 neutrons (mass number 12)
* Carbon-14: 6 protons and 8 neutrons (mass number 14)
Both are carbon (same atomic number), but Carbon-14 is heavier due to the extra neutrons.
Key Points:
* Isotopes of an element have the same chemical properties because they have the same number of electrons and thus the same electronic configuration.
* Isotopes are common and play important roles in various fields, including nuclear chemistry, dating, and medicine.
