Final answer:
The element with the electron configuration of [Ne] 3s² 3p⁵ is chlorine (Cl), which can be determined by using the noble gas configuration to count the electrons from that of the neon gas.
Step-by-step explanation:
The element with the electron configuration of [Ne] 3s² 3p⁵ is chlorine (Cl). When examining the periodic table, we can see that the noble gas neon (Ne) has the electron configuration of 1s² 2s² 2p⁶, which covers the first 10 electrons. Therefore, the configuration [Ne] is used as a shortcut to represent those electrons. Adding the electrons in the 3s and 3p orbitals, we count up from neon. With 2 electrons in the 3s orbital and 5 electrons in the 3p orbital, we have a total of 17 electrons. Chlorine, which is in group 17 of the periodic table, has 17 electrons, matching this configuration.
It is important to understand the concept of noble gas configuration to simplify the description of electron configurations. It utilizes the electron configuration of the nearest noble gas of a lower atomic number to abbreviate the inner electrons, making it easier to identify the valence electrons and, therefore, the chemical properties of the element. For example, the noble gas configuration for sodium (Na) is [Ne] 3s¹. This tells us it has the same inner-shell electron configuration as neon plus one valence electron in the 3s orbital.
Understanding electron configurations helps us determine the placement of elements on the periodic table, predict their chemical behavior, and identify elements as metals, nonmetals, or metalloids.