Privacy Policy. Skip to main content. Atoms, Molecules, and Ions. Search for:. Naming Compounds Naming Ionic Compounds An ionic compound is named first by its cation and then by its anion. Learning Objectives Convert between the chemical formula of an ionic compound and its name.
Key Takeaways Key Points Most cations and anions can combine to form neutral compounds typically solids under normal conditions that are usually referred to as salts. The net charge of an ionic compound must be zero. Therefore, the number of cations and anions in an ionic compound must be balanced to make an electrically neutral molecule. When naming ionic compounds, the cation retains the same name as the element. Key Terms Stock system : A system of naming that includes using Roman numerals to indicate the charge on transition metals.
Naming Molecular Compounds Molecular compounds are named using a systematic approach of prefixes to indicate the number of each element present in the compound. Learning Objectives Apply the rules for naming molecular compounds. Key Takeaways Key Points In nomenclature of simple molecular compounds, the more electropositive atom is written first and the more electronegative element is written last with an -ide suffix.
The Greek prefixes are used to dictate the number of a given element present in a molecular compound. Common exceptions exist for naming molecular compounds, where trivial or common names are used instead of systematic names, such as ammonia NH 3 instead of nitrogen trihydride or water H 2 O instead of dihydrogen monooxide. Key Terms nomenclature : A set of rules used for forming the names or terms in a particular field of arts or sciences. Naming Acids and Bases Acid names are based on the anion they form when dissolved in water; base names follow the rules for ionic, organic, or molecular compounds.
Learning Objectives Convert between the structure of an acid or base and its chemical name. Key Takeaways Key Points Acids are named based on their anion — the ion attached to the hydrogen.
In simple binary acids, one ion is attached to hydrogen. Complex acid compounds have oxygen in them. Weak bases are named like molecular compounds or organic compounds. Key Terms polyatomic ion : A charged species ion composed of two or more atoms covalently bonded. Also known as a molecular ion. Naming Hydrates The name of a hydrate follows a set pattern: the name of the ionic compound followed by a numerical prefix and the suffix -hydrate.
Learning Objectives Generate the chemical formula and systematic name of a given inorganic hydrate. An anhydride is a hydrate that has lost water. A substance that does not contain any water is referred to as anhydrous.
In organic chemistry, a hydrate is a compound of water, or its elements, with another molecule. Glucose, C 6 H 12 O 6 , was originally thought of as a carbohydrate carbon and water , but this classification does not properly describe its structure and properties.
Key Terms hydrate : A solid compound containing or linked to water molecules. Learning Objectives Recognize when it is appropriate to use a common chemical name. Key Takeaways Key Points Many frequently used chemicals have familiar common names.
A single substance can have several such names. The number of protons are not suppose to be equal to the number of electrons? How come we are How do you calculate the total number of protons and electrons in a polyatomic Ion. Do you have Question e03c2. Question d. Question Question 79c1f. We therefore need a series of rules that allow us to unambiguously name positive and negative ions before we can name the salts these ions form.
Some metals form positive ions in more than one oxidation state. One of the earliest methods of distinguishing between these ions used the suffixes -ous and -ic added to the Latin name of the element to represent the lower and higher oxidation states, respectively. Chemists now use a simpler method, in which the charge on the ion is indicated by a Roman numeral in parentheses immediately after the name of the element.
Negative ions that consist of a single atom are named by adding the suffix -ide to the stem of the name of the element. Predict the formula of the compound that forms when magnesium metal reacts with nitrogen to form magnesium nitride.
Click here to check your answer to Practice Problem 4. At first glance, the nomenclature of the polyatomic negative ions in the table above seems hopeless.
There are several general rules, however, that can bring some order out of this apparent chaos. The name of the ion usually ends in either -ite or -ate. The -ite ending indicates a low oxidation state. Thus,the NO 2 - ion is the nitrite ion. The -ate ending indicates a high oxidation state.
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