State the number of valence electrons for a chloride ion in an ionic bond.
To determine the number of valence electrons for a chloride ion in an ionic bond, we need to first understand the concept of valence electrons.
Valence electrons are the outermost electrons of an atom, located in its highest energy level, also known as the valence shell. These electrons are involved in chemical bonding and determine the reactivity and the bonding behavior of the atom.
In the case of chlorine (Cl), it is a halogen element in Group 7A (17) of the periodic table. Chlorine has an atomic number of 17, indicating that it has 17 electrons. The electron configuration of chlorine is 2-8-7, meaning that it has two electrons in the first energy level, eight electrons in the second energy level, and seven electrons in the third energy level.
To achieve a stable configuration, chlorine must gain one electron to fill its third energy level. This occurs when chlorine forms an ionic bond by gaining an electron from another atom or ion. In this process, chlorine becomes negatively charged and forms a chloride ion, Cl-.
Since chlorine gains one electron to form a chloride ion, the chloride ion has a total of 18 electrons. It retains the same electron configuration as a neutral chlorine atom (2-8-7) but with an extra electron.
Therefore, the number of valence electrons for a chloride ion in an ionic bond is 7 since it retains its original valence of 7 electrons when gaining an additional electron.