If E is the symbol for an element, the two symbols which represent isotopes of the same chemical element are: A and D.
Isotopes can be defined as two or more forms of a chemical element that comprises equal atomic number (numbers of protons) and electrons but different numbers of neutrons.
The isotope of an element is denoted by [tex]X_Z^A[/tex]
Where;
- X is the symbol of the chemical element.
- A is the atomic mass or mass number (number of nucleons).
- Z is the atomic number or number of protons.
If the mass number = 20
Atomic number (numbers of protons) = 10
[tex]Number\;of\;neutron = A - Z\\\\Number\;of\;neutron = 20 - 10[/tex]
Number of neutron = 10
Note: The answer option with the same atomic number (numbers of protons) but different mass number is A and D.
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