Key Takeaways

Key PointsMost cations and anions can integrate to form neutral compounds (typically solids under common conditions) that are usually referred to as salts.The net charge of one ionic compound have to be zero. Therefore, the variety of cations and anions in one ionic compound have to be balanced to make an electrically neutral molecule.When naming ionic compounds, the cation maintain the same name together the element. The anion’s name is similar to the element name, but the ending of the name has actually been removed and also replaced v “-ide.”If a metallic facet has cations of different charges, i m sorry cation is used has to be shown by that suffix (an larger method) or by roman numerals in parentheses after ~ its name in creating (the Stock mechanism ).Key TermsStock system: A mechanism of specify name that consists of using roman numerals to indicate the fee on transition metals.

You are watching: What does a roman numeral tell you when it is written after an element


In chemistry, one ionic link is a chemical link in which ions are held together by ionic bonds. Usually, the positively charged section consists of metal cations and the negative charged section is one anion or polyatomic ion. Ionic compounds have high melting and boiling points, and they often tend to be hard and brittle.

Ions have the right to be single atoms, as the sodium and also chlorine in typical table salt (sodium chloride), or more complex (polyatomic) teams such as the carbonate in calcium carbonate. However to be thought about an ion, lock must carry a confident or an adverse charge. Thus, in one ionic bond, one ‘bonder’ must have a positive charge and the various other a an unfavorable one. By difficult to each other, they resolve, or partially resolve, their different charge imbalances. Positive to confident and negative to an unfavorable ionic bonds execute not occur.

Most cations and also anions can integrate to kind solid compounds that room usually well-known as salts. The one overriding necessity is the the result compound must be electrically neutral: thus the ions Ca2+ and Br– incorporate only in a 1:2 proportion to kind calcium bromide, CaBr2. Because no other easier formula is possible, there is no should name the “calcium dibromide.” CaBr2 deserve to be named using either the Stock an approach or the older, classic way of naming.

For example, CuCl2 indicates a molecule where one Cu2+ cation associates through two Cl– anions to type a neutral compound. Its organized name is copper (II) chloride, wherein copper’s oxidation number is shown in parentheses. Its older name is cupric chloride.

The Stock method of Naming

An ionic link is named first by that is cation and then by its anion. The cation has the exact same name together its element. Because that example, K+1 is called the potassium ion, simply as K is referred to as the potassium atom. The anion is called by acquisition the elemental name, remove the ending, and adding “-ide.” because that example, F-1 is called fluoride, because that the elemental name, fluorine. The “-ine” to be removed and also replaced with “-ide.” To name a compound, the cation name and also the anion named are included together. For example, NaF is also known as salt fluoride.

If either the cation or the anion to be a polyatomic ion, the polyatomic ion surname is used in the name of the all at once compound. The polyatomic ion name continues to be the same. For example, Ca(NO3)2 is dubbed calcium nitrate.

For cations the take top top multiple charges (typically shift metals), the fee is written using Roman numerals in parentheses instantly following the element name. For example, Cu(NO3)2 is copper (II) nitrate, since the fee of two nitrate ion (NO3−1) is 2(-1) = -2. Due to the fact that the net fee of the ionic compound should be zero, the Cu ion has a 2+ charge. This compound is therefore, copper (II) nitrate. The roman numerals in fact show the oxidation number, yet in simple ionic link this will constantly be the very same as the metal’s ionic charge.

The Old, Classic, or Common method of Naming


Names of some ionic compounds: Common, or trivial, name of compound are sometimes used in unshened conversations in between chemists, specifically older chemists. Organized names space formal names that are constantly used in print.


Since part metallic elements type cations that have different positive charges, the surname of ionic compounds acquired from these aspects must contain part indication the the cation charge. The older technique uses the suffixes -ous and also -ic to denote the lower and greater charges, respectively. In the situations of iron and copper, the Latin surname of the aspects are used (ferrous/ferric, cuprous/cupric). This device is still used, although it has actually been official supplanted by the an ext precise, if slightly cumbersome, share system. In both systems, the name of the anion end in -ide.


Key Takeaways

Key PointsIn nomenclature of an easy molecular compounds, the an ext electropositive atom is written very first and the much more electronegative facet is composed last through an -ide suffix.The Greek prefixes are provided to dictate the variety of a given element present in a molecule compound.Prefixes can be shortened when the finishing vowel that the prefix “conflicts” through a starting vowel in the compound.Common exception exist for naming molecule compounds, whereby trivial or usual names are used rather of methodical names, such as ammonia (NH3) instead of nitrogen trihydride or water (H2O) rather of dihydrogen monooxide.Key Termsnomenclature: A set of rules used for creating the name or terms in a specific field of art or sciences.electronegative: Tending to tempt electrons in ~ a chemistry bond.electropositive: Tending come not entice electrons (repel) in ~ a chemical bond.

Chemical Nomenclature

The primary function of chemical nomenclature is to ensure that a spoken or written chemical name leaves no ambiguity worrying to what chemical link the surname refers. Each chemical name have to refer come a single substance. Today, scientists regularly refer to chemicals by their usual names: for example, water is no often dubbed dihydrogen oxide. However, the is important to have the ability to recognize and name all chemicals in a standardized way. The most widely embraced format because that nomenclature has actually been established by IUPAC.

Molecular compounds are made when two or much more elements share electron in a covalent bond to attach the elements. Typically, non-metals have tendency to re-superstructure electrons, make covalent bonds, and also thus, type molecular compounds.

Rules because that Naming molecular Compounds:

Remove the finishing of the 2nd element, and add “ide” as with in ionic compounds.When specify name molecular link prefixes are provided to dictate the number of a given element present in the compound. ” mono-” indicates one, “di-” indicates two, “tri-” is three, “tetra-” is four, “penta-” is five, and also “hexa-” is six, “hepta-” is seven, “octo-” is eight, “nona-” is nine, and also “deca” is ten.If over there is only among the first element, you deserve to drop the prefix. Because that example, CO is carbon monoxide, not monocarbon monoxide.If there room two collection in a row that sound the same when the prefix is added (they “conflict”), the extra vowel on the end of the prefix is removed. For example, one oxygen would be monooxide, but instead it’s monoxide. The extra o is dropped.

Generally, the much more electropositive atom is composed first, followed by the much more electronegative atom with an suitable suffix. Because that example, H2O (water) have the right to be dubbed dihydrogen monoxide (though it’s no usually). Organic molecules (molecules do of C and H in addition to other elements) carry out not follow this rule.

Examples the Molecular link Names:

SO2 is called sulfur dioxideSiI4 is dubbed silicon tetraiodideSF6 is called sulfur hexafluorideCS2 is dubbed carbon disulfide

Key Takeaways

Key PointsAcids space named based on their anion — the ion attached to the hydrogen. In basic binary acids, one ion is attached come hydrogen. Names because that such acids consist that the prefix “hydro-“, the first syllable of the anion, and also the suffix “-ic”.Complex acid compounds have oxygen in them. For an acid with a polyatomic ion, the suffix “-ate” indigenous the ion is replaced with “-ic.”Polyatomic ions v one extra oxygen (as contrasted to the typical polyatomic ion) have the prefix “per-” and also the suffix “-ic.”Polyatomic ions through one under oxygen have actually the suffix “-ous”; ions through two fewer have actually the prefix “hypo-” and the suffix “-ous.” strong bases v “-OH” (hydroxide) groups are named like ionic compounds. Weak bases are named like molecular compounds or essential compounds.Key Termspolyatomic ion: A charged species (ion) written of two or more atoms covalently bonded. Additionally known together a molecular ion.

Naming Acids

Acids are named by the anion they form when liquified in water. Depending upon what anion the hydrogen is enclosed to, acids will certainly have various names.

Simple acids, known as binary acids, have actually only one anion and also one hydrogen. These anions usually have actually the finishing “-ide.” together acids, this compounds room named beginning with the prefix “hydro-,” then including the an initial syllable of the anion, then the suffix “-ic.” because that example, HCl, i m sorry is hydrogen and also chlorine, is called hydrochloric acid.


Nomenclature of common acids: This chart gives the nomenclature that some typical anions and also acids


More facility acids have actually oxygen in the compound. Over there is a simple set of rules for these acids.

Any polyatomic ion with the suffix “-ate” supplies the suffix “-ic” as an acid. So, HNO3 will certainly be nitric acid.When you have a polyatomic ion through one an ext oxygen 보다 the “-ate” ion, climate your mountain will have the prefix “per-” and also the suffix “-ic.” for example, the chlorate ion is ClO3–. Therefore, HClO4 is dubbed perchloric acid.With one under oxygen 보다 the “-ate” ion, the acid will have the suffix “-ous.” for example, chlorous acid is HClO2.With two fewer oxygen 보다 the “-ate” ion, the prefix will certainly be “hypo-” and the suffix will be “-ous.” for example, instead of bromic acid, HBrO3, we have actually hypobromous acid, HBrO.

Naming Bases

Most strong bases save on computer hydroxide, a polyatomic ion. Therefore, solid bases room named complying with the rules because that naming ionic compounds. For example, NaOH is salt hydroxide, KOH is potassium hydroxide, and Ca(OH)2 is calcium hydroxide. Weak bases do of ionic compounds are also named utilizing the ionic specify name system. For example, NH4OH is ammonium hydroxide.

Weak bases are additionally sometimes molecule compounds or essential compounds due to the fact that they have covalent bonds. Therefore, they room named following the rules because that molecular or essential compounds. For example, methyl amine (CH3NH2) is a weak base. Part weak bases have actually “common” names. Because that example, NH3 is referred to as ammonia; its surname isn’t acquired from any type of naming system.


Naming Hydrates

The name of a hydrate follows a set pattern: the surname of the ionic compound adhered to by a numerical prefix and also the suffix -hydrate.


Key Takeaways

Key point out Hydrates are called by the ionic compound adhered to by a numerical prefix and the suffix “-hydrate. ” The “· nH2O” notation indicates that “n” (described by a Greek prefix) variety of loosely bonded water molecules are associated per formula unit of the salt.An anhydride is a hydrate that has lost water. A substance the does no contain any water is described as anhydrous.In organic chemistry, a hydrate is a link of water, or that elements, with another molecule. Glucose, C6H12O6, was originally thought of together a carbohydrate (carbon and also water), yet this classification does not properly define its structure and also properties.Key Termshydrate: A solid compound containing or connected to water molecules.carbohydrate: A sugar, starch, or cellulose that is a food source of power for an pet or plant; a saccharideanhydride: any kind of compound formally obtained from another (or from others) through the loss of a water molecule; a molecule through no water.

Inorganic Hydrates

“Hydrate” is a term supplied in inorganic chemistry and also organic chemistry to show that a substance includes loosely external inspection water. The name of a hydrate complies with a set pattern: the surname of the ionic compound complied with by a number prefix and the suffix “-hydrate.” because that example, CuSO4 · 5 H2O is “copper(II) sulfate pentahydrate.” The notation that hydrous compound · nH2O, where n is the number of water molecules per formula unit the the salt, is typically used to display that a salt is hydrated. The “cdot” indicates that the water is loosely external inspection to the ionic compound. The “n” is normally a low integer despite it is possible for fractional values to exist. The prefixes are the exact same Greek prefixes offered in naming molecular compounds. Therefore, in a monohydrate “n” is one; in a hexahydrate “n” is 6, and also so on.

The Greek prefixes supplied in naming hydrates because that numbers 1/2 with 10 space as follows:

1/2: hemi-1: mono-2: di-3: tri-4: tetra-5: penta-6: hexa-7: hepta-8: octa-9: nona-10: deca-

A hydrate that has actually lost water is described as one anhydride. An anhydride can normally lose water just with far-ranging heating. A substance the no much longer contains any water is described as anhydrous.

Organic Hydrates

In necessary chemistry, hydrates tend to it is in rarer. An essential hydrate is a compound formed by the enhancement of water or its elements to another molecule. Because that example, ethanol, CH3–CH2–OH, can be considered a hydrate of ethene, CH2=CH2, created by the enhancement of H come one C and OH come the other C. Another example is chloral hydrate, CCl3–CH(OH)2, which can be formed by the reaction of water v chloral, CCl3–CH=O.

Molecules have actually been labeled together hydrates for historic reasons. Glucose, C6H12O6, was originally thought of as C6(H2O)6 and also was defined as a carbohydrate, but this is a really poor description of that structure offered what is known around it today. Methanol is frequently sold as “methyl hydrate,” implying the incorrect formula CH3OH2. The correct formula is CH3–OH.


Cobalt(II) chloride hexahydrate: CoCl2·6H2O has the systematic name cobalt(II) chloride hexahydrate.


Key Takeaways

Key PointsMany typically used chemicals have actually familiar common names. A solitary substance deserve to have number of such names.Some typical names because that chemical substances have actually historical roots and have been used for thousands of years.Common chemistry names are used in spoken or informal written communication by chemists. Because that some simple compounds, your systematic and common names space the same.Key Termscommon name: The name by which a types is known to the general public, rather than that is taxonomic or scientific name.

Common surname v. Methodical Names

Many chemicals space so lot a component of everyday life that people know them by their acquainted names. Ordinary cane sugar, for example, is much more formally known as sucrose, but asking for it in ~ the dinner table by the name will most likely be a conversation stopper. Now imagine utilizing its systematic name in the exact same context: “Please happen the α-D-glucopyranosyl-(1,2)-β-D-fructofuranoside!” yet saying “sucrose” would certainly be quite ideal if you essential to identify this certain sugar native the numerous other named sugars. And also the only place you would come across a systematic name such as the rather unwieldy one mentioned above would be in scientific documentation in referral to a sugar that has no simple common name. 

Many common chemical name have an extremely old and also intriguing origins, as the adhering to two instances illustrate.

Most people associate the surname ammonia (NH3) through a gas with a pungent odor. When its organized name, “nitrogen trihydride” (which is seldom used), tells you that formula, what it will certainly not tell friend is the interesting background of the discovery. Exhilaration from burn camel dung (the staple fuel of north Africa) condenses top top cool surfaces to form a crystalline deposit, i beg your pardon the old Romans an initial noticed ~ above the walls and ceiling the the holy place that the Egyptians had constructed to the sunlight god Amun in Thebes. They called the product “sal ammoniac,” definition “salt of Amun.” In 1774, Joseph Priestly (the discoverer that oxygen) found that heater sal ammoniac created a gas through a pungent odor, which T. Bergman named “ammonia” eight years later.

Arabic alchemy has given us a number of chemical terms. Because that example, alcohol is thought to derive from the Arabic al-khwl or al-ghawl, which initially referred to a metallic powder supplied to darken women’s eyelids (kohl). Alcohol gone into the English language in the 17th century with the an interpretation of a “sublimated” substance, then changed to median the “pure spirit” the anything, and also only became connected with “spirit the wine” in 1753. Finally, in 1852, it come to be a part of chemical nomenclature the denoted a common class of essential compound. But, the is still usual practice to refer to the particular substance CH3CH2OH together “alcohol” quite than through its organized name, ethanol.

See more: Travel Distance From London To New York City And London, Distance New York City

General practices in Naming

The basic practice among chemists is to usage the an ext common chemical names whenever the is useful to execute so, specifically in talked or informal composed communication. Many of the “common” names space known and also used mostly by the scientific community. Chemical substances that are employed in the home, the arts, or in industry have actually acquired classic or “popular” surname that room still in broad use. Many, choose sal ammoniac mentioned above, have fascinating stories behind their names.


*

Sulfuric Acid: The historic name because that sulfuric mountain is “oil that vitriol”. Medieval European alchemists prepared it by roasting “green vitriol” (iron (II) sulfate) in an stole retort. Its chemistry formula is H2SO4.