# Charge number

Charge number or just valence[1] of an ion is the coefficient that, when multiplied by the elementary charge, gives the ion's charge.[2]

For example, the charge on a chloride ion, $\mathrm{Cl}^-$, is $-1 \cdot e$, where e is the elementary charge. This means the charge number for the ion is $-1$.

$z$ is sometimes used as the symbol for the charge number. In that case, the charge of an ion could be written as $Q = z e$.

For an atomic nucleus, which can be regarded as an ion having stripped off all electrons, the charge number is identical with the atomic number Z (number of protons).

In particle physics the charge number is a (derived) flavour quantum number, mostly denoted by Q (regarded as 'electric charge in units of e') rather than z. For color charged particles with like quarks and hypothetical leptoquarks the charge number is a broken multiple of 1/3.

Studying and learning the chemical charge in chemistry is very important to understand chemistry and certain properties of why events occur in our world. The charge number in chemistry normally relates to an electric charge. This is a property of specific subatomic atoms. Theses elements define the electromagnetic contact between the two elements. A chemical charge can be found by using the periodic table. Depending on the placement of the element on the periodic table can tell someone if the chemical charge is negative or positive. Looking at the figure below, one can see that the positive charges are on the left side of the table and the negative charges are on the right side of the table. Charges that are positive are called cations. Charges that are negative are called anions. Elements in the same group have the same charge. A group in the periodic table is a term used to represent the vertical columns. The figure is taken from this link: https://www.google.com/search?hl=en&gs_rn=9&gs_ri=psy-ab&cp=16&gs_id=72&xhr=t&q=periodic+table+with+charges&bav=on.2,or.r_qf.&bvm=bv.45373924,d.b2I&biw=1061&bih=600&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&tab=wi&ei=Z51wUfvRGKqa2gWTnoDIBg#imgrc=zSJB8gpDaxPsgM%3A%3BHbRSdetW6MVNUM%3Bhttp%253A%252F%252Fwww.chemistryland.com%252FCHM130S%252F06-Nomenclature%252FLanguageOfChemistry%252FOxidationNumbers.jpg%3Bhttp%253A%252F%252Fwww.chemistryland.com%252FCHM130S%252F06-Nomenclature%252FLanguageOfChemistry%252FLanguage.htm%3B512%3B344

Looking at the figure above again, notice that group 18 on the periodic table does not have a charge number. This group is called the noble gases of the periodic table. They do not have a charge because they are unreactive. They are unreactive because these atoms are already stable. Every atom strives to have eight electrons, and the noble gases, without binding with any other atom, already has eight electrons. The other atoms or ions have charges because they are very reactive and want to react with another atom or ion to become stable with eight electrons. When elements are bonded, they can either be bonded by ionic bonding or covalent bonding. When elements bind between positive and negative charged atoms, their charges will be switched and carried down on the other element to combine them equally. This is shown below. Using the chart provided, if ammonium with a plus 1 charge is combined to an ion with a negative 1 charge like acetate, the charges will be cancelled out, shown in the figure below.

〖NH〗_4^++C_2 H_3 O_2^-→〖NH〗_4 C_2 H_3 O_2

When two ions are combined with different charges, the charges do not get canceled out. They get carried over and placed at the end of the other ion. This is shown below between ammonium and carbonate.

〖NH〗_4^++〖CO〗_3^(2-)→〖(NH〗_4 )_2 〖CO〗_3

The ammonium part on the product side has to have parenthesis in order to distinguish between the ammonium subscript 4 compared to the 2 charge that has been dropped down, connected to it. The other figure can be found from this link: https://www.google.com/search?hl=en&gs_rn=9&gs_ri=psy-ab&cp=16&gs_id=72&xhr=t&q=periodic+table+with+charges&bav=on.2,or.r_qf.&bvm=bv.45373924,d.b2I&biw=1061&bih=600&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&tab=wi&ei=Z51wUfvRGKqa2gWTnoDIBg#um=1&hl=en&tbm=isch&sa=1&q=chart+of+chemical+charges&oq=chart+of+chemical+charges&gs_l=img.3...9571.14576.2.14848.35.23.6.6.6.0.246.1179.22j0j1.23.0...0.0...1c.1.9.img.bHS1to0gOUc&bav=on.2,or.r_qf.&bvm=bv.45373924,d.b2I&fp=41971f3d447c4cbb&biw=1061&bih=600&imgrc=ejCdF028RHLv6M%3A%3BgEd6FPKeNws-xM%3Bhttp%253A%252F%252Fboomeria.org%252Fchemtextbook%252Ftable4-4.jpg%3Bhttp%253A%252F%252Fboomeria.org%252Fchemtextbook%252Fcch4.html%3B544%3B361

〖NH〗_4^++C_2 H_3 O_2^-→〖NH〗_4 C_2 H_3 O_2

When two ions are combined with different charges, the charges do not get canceled out. They get carried over and placed at the end of the other ion. This is shown below between ammonium and carbonate.

〖NH〗_4^++〖CO〗_3^(2-)→〖(NH〗_4 )_2 〖CO〗_3

The ammonium part on the product side has to have parenthesis in order to distinguish between the ammonium subscript 4 compared to the 2 charge that has been dropped down, connected to it.

Charge numbers also help to determine other aspects of chemistry. One example is that someone can use the charge of an ion to find the oxidation number of a monatomic ion. For example, the oxidation number of 〖Li〗^+ is +1. This helps when trying to solve oxidation questions.

A charge number also can help when drawing lewis dot structures. For example, if the structure is an ion, the charge will be included outside of the lewis dot structure. This is shown below in the link.