What is the reason for the slightly different physical properties of all the isotopes of an element?

Q. What is the reason for the identical chemical properties of all the isotopes of an element?

Q. define The isotopes of an element have the same physical properties.

Q. Which of the following are characteristics of isotopes of an element?
$\left(i\right)$ Isotopes of an element have the same atomic masses.
$\left(ii\right)$ Isotopes of an element have the same atomic number.
$\left(iii\right)$ Isotopes of an element show the same physical properties.
$\left(iv\right)$ Isotopes of an element show the same chemical properties.

Q. What is the reason for the different atomic masses of the isotopes of an element?