18elektronkonfiguration

18elektronkonfiguration refers to the electron configuration of an atom or ion that possesses a total of 18 electrons. This configuration is characteristic of the noble gas Argon (Ar), which has an atomic number of 18. In its ground state, an Argon atom has 18 protons and 18 electrons. The electron configuration of Argon is 1s²2s²2p⁶3s²3p⁶. This arrangement signifies that the first electron shell (n=1) contains 2 electrons in the 1s orbital, the second electron shell (n=2) contains 8 electrons (2 in the 2s orbital and 6 in the 2p orbitals), and the third electron shell (n=3) contains 8 electrons (2 in the 3s orbital and 6 in the 3p orbitals). This full outer electron shell makes Argon chemically unreactive, as it has achieved a stable electron configuration.

Several ions can also exhibit an 18-electron configuration. For example, potassium (K), with atomic number 19, loses one electron to form the K⁺ ion, which then has 18 electrons. Its electron configuration is identical to Argon's: 1s²2s²2p⁶3s²3p⁶. Similarly, calcium (Ca), with atomic number 20, loses two electrons to form the Ca²⁺ ion, also resulting in an 18-electron configuration. Chlorine (Cl), atomic number 17, gains one electron to form the Cl⁻ ion, achieving the same stable 18-electron configuration. Sulfur (S), atomic number 16, gains two electrons to form S²⁻, and phosphorus (P), atomic number 15, gains three electrons to form P³⁻, all resulting in an 18-electron configuration. These ions are isoelectronic with Argon, meaning they have the same number of electrons and the same electron configuration.