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What’s in the Name? - Atoms, Ions and Compounds
What’s in the Name? - Atoms, Ions and Compounds
Learning Objectives:
Learning Objectives:
Upon completion of this experiment, students will have experienced:
(MLO2-7) Predict from the elements present in a compound whether it contains ionic or covalent bonds.
(MLO3-1) Predict the charge of an ion formed utilizing the number of valence electrons and its location on the periodic table.
(MLO3-2) Apply the rules of nomenclature to write formulas or to name ionic compounds, molecular compounds and acids
(MLO3-3) Identify polyatomic ions, their formula and charge.
Experiment 5 reviews and explains how to identify, name and write compounds.
The assignments that must be completed and submitted in Canvas are the following:
The assignments that must be completed and submitted in Canvas are the following:
Laboratory Report of the experiment using the resources listed below
Discussion
Discussion
Atoms are the smallest structure of elements that make up every substance around us. Elements are pure, but compounds are formed chemically from the elements. There are many compounds that exist around us and these can be classified into simple groups. Atoms form chemical bonds by either sharing electrons or forming ions that then combine to balance their individual charges.
In this experiment, you will need to name compounds given their formulas or write the formula of a compound from its name. Compounds can come in many different forms but we can separate most compounds into four types as shown below (ionic, metallic, acids and molecular). Each of these can further be separated into more categories such binary, 2 elements, or ternary, 3 or more elements. How we recognize the type of compound and therefore the naming scheme is an important task. Ionic compounds can be either binary or ternary but they generally have both metal and non metal elements present in the compound. Generally when we write the elements in a compound, we list the least electronegative atom first (beginning with the lower left of the periodic table) and order the elements from least to most electronegative (upper Right corner) Fluorine is always written last in a formula. Hydrogen, however, can often be written first, last or anywhere in between, not following the previous rule. Where Hydrogen is placed often gives a clue as to the type of compound.
Compounds
Compounds
Ionic and Covalent compounds:
Chemical and Molecular formula:
Each of the above naming schemes will be discussed. The most important item to get from the lab are how do you identify the type of compound so that you can place it into the proper group.
Ionic compounds are made of ions
Ionic compounds are made of ions
Cations can be metal ions of the metallic elements that carry only one possible oxidation state or many possible oxidation states or ammonium ion - Mn+,or the polyatomic cation, ammonium, NH4+ . The cations take the same name as the element followed by the value of the charge the metal carries if there are more than one possible oxidation state for the metal.
Anions can be monatomic ions of the non metallic elements that always are written as the root name of the element followed by the ending -ide or the polyatomic ions. These ions can end with ide, ite or ate. The best way to know these are to memorize them for the test and later work . The common polyatomic anions are nitrate: NO31-, chlorate: ClO31-. carbonate: CO32-, sulfate: SO42-, phosphate: PO43-, acetate: C2H3O21- . Cyanide: CN1-, hydroxide: OH1-, Peroxide: O22- . A few rules can then be used to name additional polyatomic ions ending in ite or begin with per-, hypo- or hydrogen.
Appendix E-PeriodicTable.pdfOne basic naming rule should be observed in naming ionic compounds, the cations are always named first, followed by the name of the anions. In general all ionic compounds use a similar pattern when naming the ions present in the compound.
name of cation (charge of the metal ion, if needed) name of anion
In general all ionic compounds use a similar pattern. when we write the formula from the name. First the oxidation states of each of the ions must be determined. These charge on the cation multiplied by the subscript on the ion added to the charge on the anion multiplied by the subscript of the anion must add up to equal the charge on the neutral compound (add to zero). The common oxidation states of the elements are given below. The charges shown for the monatomic anions of non metals are the oxidation state of the ion in a binary ionic compound.
formula of cation (element or Ammonium ion) subscript to balance charge formula of anion (element or polyatomic) subscript to balance charge
formula of cation (element or Ammonium ion) subscript to balance charge formula of anion (element or polyatomic) subscript to balance charge
Some salts (another word for ionic compounds) can exist as a hydrated salt where the water is linked directly to the metallic element through looser interactions called chelated structures. We call these salts hydrated. Salts can also be anhydrous if the water is removed by heating.
ionic compound name - prefix of number hydrate
Tyler DeWitt's Videos on Naming Compounds (Nomenclature)
Tyler DeWitt's Videos on Naming Compounds (Nomenclature)
Writing chemical formula
Writing chemical formula
Acids
Acids
Acids are generally always written with hydrogen in the first position, unless we are dealing with organic acids. The name of the acid is dependent upon the name of the anion. Hydrogen followed by an anion's name is generally not considered to be an acid. An acid generally only exists in an aqueous solution. Like ionic compound the formula of an acid uses subscripts on the hydrogen ion, H+, and the anion.
The name of the acid is dependent upon the name of the monoatomic or polyatomic anion.
If the anion ends in –ide, then the acid is named hydro + root of the anion + ic acid
If the anion ends in –ate, then the acid is named by taking the root + ic acid
If the anion ends in –ite, then the acid is named by taking the root + ous acid
Molecular compounds
Molecular compounds
Molecular compounds have two non metallic elements bonding. Like the hydrated salt, prefixes are used to tell how many of each element is present. Molecular compounds can be either inorganic or organic. The prefixes used for these naming schemes are different. Inorganic molecular compounds are generally only binary compounds and therefore the naming scheme is simple:
prefix of number - name of first element - prefix of number - root of second element with - ide
Organic or hydrocarbon compounds
Organic or hydrocarbon compounds
Hydrocarbons begin with Carbon and Hydrogen but may also contain several other non metallic elements. The naming scheme for organic compounds is much more complicated than naming ionic or inorganic compounds.
The following images are schemes for naming or determining the formula of compounds.
Tyler DeWitt's Videos on Naming Compounds (Nomenclature)
Tyler DeWitt's Videos on Naming Compounds (Nomenclature)
Pre laboratory assignment
Pre laboratory assignment
The Pre laboratory problems are questions about the laboratory assignment, background, definitions or procedure and calculations. These problems should be completed BEFORE coming to the class where the assignment will be discussed.
There are 27 compounds that must be separated into 9 groups of 3 compounds.
Compound Cards: pdf format or google doc.
You can use these cards to separate the 27 compounds into their respective groups. Use the Experiment 5 lecture above to help you complete this assignment.
Report
Report
The laboratory report walks through the various types of compounds with examples. Complete each of the tables (A through L) in the laboratory report. Use the following video resources to complete this assignment.
11 videos of Chemical Nomenclature
Namng Compounds:
Formula of Compounds:
Molecular Compounds
Writing Formula: http://youtu.be/DFw3AW2BFUw
Naming: http://youtu.be/VokWJy_jpAc
Ionic Compounds
Writing Formula: http://youtu.be/URc75hoKGLY
naming: http://youtu.be/7Lfc6jjp1WQ
Polyatomic ions
writing formula: http://youtu.be/p9iQ5Qn42DM
naming: http://youtu.be/FIXHIbStAZs
Acids
Post Laboratory Problems
Post Laboratory Problems
The Post laboratory problems contain questions that determine your understanding of the laboratory assignment. Complete all the problems either determining the name from the formula or the formula from a name of the compound. There is no conclusion paragraph for this experiment.
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