The Correct Answer and Explanation is:
To generate the correct answers, determine the number of protons, neutrons, and electrons in each isotope using the atomic number (Z) and mass number (A).
- Protons = Atomic number (Z)
- Neutrons = Mass number (A) minus Atomic number (A − Z)
- Electrons = Same as protons in a neutral atom
a)
Isotope: 2040Ca^{40}_{20}\text{Ca}2040Ca
- Protons: 20
- Neutrons: 40 − 20 = 20
- Electrons: 20
b)
Isotope: 1840Ar^{40}_{18}\text{Ar}1840Ar
- Protons: 18
- Neutrons: 40 − 18 = 22
- Electrons: 18
c)
Isotope: 52127Te^{127}_{52}\text{Te}52127Te
- Protons: 52
- Neutrons: 127 − 52 = 75
- Electrons: 52
d)
Isotope: 84209Po^{209}_{84}\text{Po}84209Po
- Protons: 84
- Neutrons: 209 − 84 = 125
- Electrons: 84
e)
Isotope: 63152Eu^{152}_{63}\text{Eu}63152Eu
- Protons: 63
- Neutrons: 152 − 63 = 89
- Electrons: 63
Explanation
Atoms are composed of protons, neutrons, and electrons. The atomic number is the number of protons, which identifies the element. The mass number is the sum of protons and neutrons in the nucleus. Electrons in a neutral atom are equal to the number of protons because their negative charge balances the positive charge of the protons.
The difference between isotopes of the same element is in the number of neutrons. For example, calcium-40 and calcium-42 both have 20 protons but different numbers of neutrons. This difference affects the atomic mass but not the chemical properties significantly.
Understanding these subatomic particles is fundamental in atomic theory, nuclear chemistry, and radiation studies. Neutrons play a key role in isotope stability. A change in proton number results in a new element, while a change in neutron count results in a different isotope of the same element.
