What is the element with the electron configuration 1s2 2s2 2p6 3s2 3p5
The correct answer and explanation is :
The element with the electron configuration (1s^2 2s^2 2p^6 3s^2 3p^5) is Chlorine (Cl).
Explanation:
Electron configurations describe how electrons are arranged in an atom. These arrangements are important because they determine the chemical properties and reactivity of elements. The electron configuration provided is (1s^2 2s^2 2p^6 3s^2 3p^5), which represents an atom with electrons filling specific orbitals in order.
Here’s how we break down this electron configuration:
- 1s²: The “1” indicates the first energy level, and “s” refers to the shape of the orbital (s orbitals can hold a maximum of 2 electrons). This means there are two electrons in the first energy level.
- 2s²: The “2” indicates the second energy level, and “s” again represents an s orbital. This shell can hold 2 electrons, and there are 2 electrons in the 2s orbital.
- 2p⁶: The “p” orbital can hold a maximum of 6 electrons. Here, there are 6 electrons in the second energy level’s p orbitals.
- 3s²: In the third energy level, we have 2 electrons in the s orbital.
- 3p⁵: Lastly, in the third energy level, there are 5 electrons in the p orbitals.
So, if we count all the electrons, we get a total of 17 electrons (2 from (1s), 2 from (2s), 6 from (2p), 2 from (3s), and 5 from (3p)).
Since the number of protons in a neutral atom equals the number of electrons, this atom also has 17 protons. The element with atomic number 17 is Chlorine (Cl). Chlorine is a halogen found in Group 17 (VIIA) of the periodic table, and it has chemical properties typical of halogens, such as its tendency to form salts when combined with metals (e.g., sodium chloride, NaCl). Chlorine typically gains one electron to achieve a stable, noble gas electron configuration.