Final answer:
Oxygen (O) is the element that has four electrons in its 2p sublevel, according to its electron configuration and Hund's rule. Option A is correct.
Step-by-step explanation:
The element that has four electrons in its 2p sublevel is Oxygen (O). According to electron configuration principles and Hund's rule, when adding electrons to the 2p sublevel, one electron enters each orbital before any orbital receives a second electron.
Since Oxygen has an atomic number of 8, its electron configuration is 1s² 2s² 2p⁴. This means the first two energy levels are filled with two electrons each, and the remaining four electrons are in the 2p sublevel: two in each of the two orbitals, with each pair having opposite spins.
The element with 4 electrons in its 2p sublevel is Oxygen (O). The 2p sublevel consists of three orbitals, and according to Hund's rule, each orbital is filled with one electron before any orbital receives a second electron. Therefore, Oxygen has one electron in each of the three 2p orbitals, and the fourth electron goes into the first 2p orbital with a spin opposite to the other electron in that orbital.