Isotopes have different _______ number, because their nuclei contain different number of ________.
Isotopes: Isotopes are the atoms of the same elements that have same atomic number but different mass number. Example: and are isotopes of Chlorine (Cl)
Atomic number (Indicated as subscript) is same for both of the isotopes i.e.; 17.
Mass number (Indicated as superscript) is different for both the isotopes i.e.; 35 and 37.
The value of neutrons, which are present inside the nucleus along with the protons) for both of the isotopes are listed below.
Isotope | ||
Mass number | 35 u | 37 u |
Number of neutrons | 35-17= 18 | 37- 17= 20 |
Therefore, isotopes have different mass number, because their nuclei contain different number of neutrons.