Question

The 71 th electron of an element X with an atomic number of 71 entres into the orbital

Answer 1

Answer: The electron will enter the 5d orbital.

Explanation:

Filling of electrons usually follow many rules, but what orbit the electron will enter is given the Aufbau rule.

This rule states that electrons will be filled in the atomic orbitals which are low in energy than the atomic orbitals which have high energy. The filling of atomic orbitals follow the order 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s and so on....

For the element X having atomic number 71 has 71 electrons.

The electronic configuration of this element is: $1s^22s^22p^63s^23p^64s^23d^{10}4p^65s^24d^{10}5p^66s^24f^{14}5d^1$

From the above configuration, it is visible that the 71st electron is entering the 5d orbital.

Answer 2

Answer:

The correct answer is 5d