Electron Configuration For Chlorine Ion

Learning Objective

Predict whether an atom will undergo ionization to provide an anion or cation based on its valence beat out electron configuration.

Key Points

The electronic configuration of many ions is that of the closest noble gas to them in the periodic table.
An anion is an ion that has gained 1 or more than electrons, acquiring a negative accuse.
A cation is an ion that has lost one or more electrons, gaining a positive charge.

Terms

cationA positively charged ion, equally opposed to an anion.
ionizationAny process that leads to the dissociation of a neutral atom or molecule into charged particles (ions).
anionA negatively charged ion, as opposed to a cation

Cations and Anions form from Neutral Atoms

Every atom in its ground land is uncharged. It has, according to its atomic number, the aforementioned number of protons and electrons. Electrons are rather labile, even so, and an cantlet will ofttimes gain or lose them depending on its electronegativity. The driving force for such gain or loss of electrons is the energetically optimal land of having a full valence (outermost) shell of electrons. In such a country, the resulting charged atom has the electron configuration of a noble gas.

Improver of an electron will disrupt the proton-electron residual and leave the atom negatively charged. Removal of an electron will, conversely, leave the cantlet positively charged. These charged atoms are known as ions.

Formation of Monatomic Ions

Monatomic ions are formed by the addition or removal of electrons from an cantlet'southward valence crush. The inner shells of an atom are filled with electrons that are tightly bound to the positively charged diminutive nucleus then practise not participate in this kind of chemical interaction, only the valence shell can exist very reactive depending on the atom and its electron configuration. The process of gaining or losing electrons from a neutral atom or molecule is called ionization.

Atoms tin be ionized by bombardment with radiation, but the more purely chemic process of ionization is the transfer of electrons between atoms or molecules. This transfer is driven by the stabilization that comes by obtaining stable (full shell) electronic configurations. Atoms will gain or lose electrons depending on which action takes the least free energy.

For example, Group 1 chemical element sodium (Na) has a single electron in its valence shell, with full shells of two and 8 electrons beneath. Removal of this ane electron leaves sodium stable: Its outermost shell now contains 8 electrons, giving sodium the electron configuration of neon. Having gained a positive charge, the sodium ion is called a cation. The ionization of sodium can be chemically illustrated as follows:

Na → Na⁺ + e⁻

Sodium could gain electrons, but it would require seven more to accomplish a full valence shell. Removing one electron is much easier than gaining seven, and thus sodium will in every chemic scenario reach its octet past condign a cation.

On the other hand, a chlorine cantlet (Cl) has vii electrons in its valence shell, which is one short of a stable, full vanquish with viii electrons. Thus, a chlorine atom tends to proceeds an extra electron and reach a stable 8-electron configuration (the same as that of argon), condign a negative chloride anion in the process:

Cl + e− → Cl⁻

Combining the propensity of sodium to lose an electron and of chloride to gain an electron, we observe complimentary reactivity. When combined, the uncharged atoms can substitution electrons and in doing so, accomplish complete valence shells. The resulting ions stick together due to ionic bonds (opposite charges attract), leaving a crystal lattice structure of NaCl, more commonly known as rock salt. The reaction is equally follows:

Na⁺ + Cl⁻ → NaCl

Polyatomic and Molecular Ions

Ionization is not limited to individual atoms; polyatomic ions can likewise be formed. Polyatomic and molecular ions are ofttimes created by the addition or removal of elemental ions such as H⁺ in neutral molecules. For example, when ammonia, NH₃, accepts a proton, H⁺, it forms the ammonium ion, NH₄ ⁺. Ammonia and ammonium take the aforementioned number of electrons in essentially the same electronic configuration, but ammonium has an extra proton (the H⁺) that gives it a cyberspace positive charge.

Chemical Notation

When writing the chemical formula for an ion, its net charge is written in superscript immediately subsequently the chemic construction for the molecule or cantlet. The net charge is written with the magnitude before the sign, that is, a doubly charged cation is indicated as 2+ instead of +2. All the same, the magnitude of the charge is omitted for singly charged molecules or atoms; for example, the sodium cation is indicated as Na⁺ and non Na¹⁺.

An alternative way of showing a molecule or atom with multiple charges is by drawing out the signs multiple times; this is often seen with transition metals. Chemists sometimes circle the sign; this is simply ornamental and does not change the chemical meaning. A twice-positively charged iron atom tin also be expressed as Atomic number 26ⁱⁱ⁺ or Fe⁺⁺.

In the case of transition metals, oxidation states can exist specified with Roman numerals; for case, Feⁱⁱ⁺ is occasionally referred to as Fe(II) or Fe^II. The Roman numeral designates the formal oxidation state of an element, whereas the superscripted numerals denotes the net charge. The two notations are therefore exchangeable for monatomic ions, only the Roman numerals cannot be applied to polyatomic ions. However, information technology is possible to mix the notations for the individual metallic middle with a polyatomic circuitous, as demonstrated using the uranyl ion (UO₂) as an example.

It should exist noted that information technology is possible to remove many electrons from an cantlet. The energy required to do so may be recorded in a successive ionization free energy diagram.