Strontium has 3 stable isotopes with mass numbers 86, 87 and 88. Their relative abundances are 9.97%, 7.0% and 82.6% respectively. How do the number of electrons and the electron configurations compare for atoms of the three isotopes

38 and [Kr] 5s2.

Explanation:

The number of electrons and the electronic configurations are the same for the three isotopes of Strontium because in isotopes number of neutron increases not number of proton or electron. Isotope of element having the same atomic number but with different atomic masses due to increase the number of neutrons in each isotope. So the number of electron in all isotopes are the same i.e. 38 and the electronic configuration is also the same i.e. [Kr] 5s2.