Which element has the electron configuration 1s2 2s2 2p6 3s2 3p5?
A) Oxygen
B) Fluorine
C) Sulfur
D) Chlorine
E) Bromine
The Correct Answer and Explanation is :
The element with the electron configuration 1s² 2s² 2p⁶ 3s² 3p⁵ is D) Chlorine.
Chlorine’s atomic number is 17, which means it has 17 electrons. The electron configuration is written based on how electrons fill up the atomic orbitals according to the rules of quantum mechanics. The order in which electrons fill these orbitals is based on the energy levels and sublevels.
- 1s orbital: The first two electrons fill the 1s orbital, giving us 1s².
- 2s orbital: The next two electrons go into the 2s orbital, resulting in 2s².
- 2p orbitals: The next six electrons fill the 2p orbitals completely, which is represented as 2p⁶. At this point, we have a total of 10 electrons, which is the electronic structure of Neon, a noble gas.
- 3s orbital: The eleventh and twelfth electrons enter the 3s orbital, giving 3s².
- 3p orbitals: The next five electrons begin to fill the 3p orbitals. Since there are three 3p orbitals, the first three electrons each occupy one orbital (according to Hund’s Rule, which states that electrons fill empty orbitals first before pairing up). The fourth and fifth electrons then pair up with two of the electrons in the singly occupied orbitals, leading to the configuration 3p⁵.
This configuration matches chlorine, which is in Group 17 (the halogens) of the periodic table. Halogens are known for having seven electrons in their outermost p orbital, which makes them highly reactive as they seek to gain one more electron to achieve a stable noble gas configuration.
Chlorine is used widely as a disinfectant and in the production of various chemicals. Its high reactivity is attributed to its electron configuration, which makes it eager to accept an electron to form a chloride ion, thereby achieving a stable electron configuration similar to the noble gases.
Now, let’s generate an image that illustrates chlorine’s electron configuration visually.
Here is the illustration showing the electron configuration of Chlorine, with each orbital clearly labeled and the arrangement of electrons depicted as per the description. This visual should help clarify how the electrons are distributed in the atom of Chlorine.
