Chapter 5 Types of Compounds

Section 5.1 Ionic Compounds

Binary Compounds A compound that contains only two elements. Example: Sodium chloride (NaCl) Potassium Iodide (KI) Calcium fluoride (CaF2)

Naming Binary Compounds First write the name of the positively charged ion (metal) Then add the name of the negatively charged ion, (nonmetal) Change the ending of the nonmetal’s name to include “ide” Example: NaCl (sodium chlorine) sodium chloride (The metal is always written first)

(don’t worry about the subscripts for now) Check Point Complete the names of the following binary compounds: Na3N sodium ________________ MgBr2 magnesium ________________ Al2O3 aluminum ________________ CaS _________ _______________ (don’t worry about the subscripts for now)

Binary Compound Formulas Compounds are electrically neutral. The sum of the charges in an ionic compound are neutral. Example: In the compound NaCl One Na+ balances out one Cl -

Formula Unit The lowest whole number ratio of ions in an ionic compound. Ionic compounds do not form molecules.

Predicting Charges A neutral atom becomes “charged” when it has lost or gained valence electrons. All elements in a group have the same number of valence electrons so they must lose or gain the same number of electrons to achieve stability. Charges on an ion are known as its oxidation number. Group numbers can be used to predict charges.

Charges for Groups

Predict the charges of the following elements: Check Point Predict the charges of the following elements: Mg _________ S _________ Li _________ Al _________

The Criss-Cross Method 1. Write the element’s symbol for the metal (cation) and the nonmetal (anion). Al S 2. Use a superscript for the charge (+/-) of each ion. Al + 3 S - 2

3. Criss-cross the superscript of the cation to the subscript position of the anion (disregard the positive sign). 4. Criss-cross the superscript of the anion to the subscript position of the cation (disregard the negative sign).

4. Rewrite your final answer. 5 4. Rewrite your final answer. 5. If possible, divide the subscripts by their greatest common factor to reduce to simplest whole ratio. Example: Ni4O2 Ni2O

Write the formula for the following compounds: Check Point Write the formula for the following compounds: Sodium and Sulfur _________ Magnesium and Bromine _________ Aluminum and Oxygen _________

Polyatomic Ions An ion that has two or more different elements. The group of atoms has an overall charge. The names and formulas for these ions are found on the back of your periodic table. The ending of polyatomic ions does not get changed.

Polyatomics

Formulas w/ Polyatomic ions Treat the polyatomic ion as if it was a single element by keeping it together as a unit (that includes its subscripts). Multiples of a polyatomic ion in a formula can be indicated by placing parentheses around the entire ion (including its subscripts) and then writing a new subscript outside of the parentheses to show the number of polyatomic ions.

Practice Write the formula for aluminum sulfate: Criss-Cross (don’t touch the ”4” subscript in the sulfate). Use parentheses in your final answer.

Write the formula for the following compounds: Check Point Write the formula for the following compounds: Sodium and carbonate _________ Magnesium and hydroxide _________

Transition Metals & Charges Many transition metals may have more than one charge. Since many transition metals can have more than one possible charge they MUST have a Roman Numeral to indicate the charge on the individual ion. Example: Fe2+ iron(II) ion Fe3+ iron(III) ion

Roman Numerals Number Roman Numeral 1 I 2 II 3 III 4 IV 5 V 6 VI 7 Vii 8 Viii 9 IX 10 X

Check Point Indicate the charge on the following: Copper (II) _________ Iron (III) _________ Indicate the name of the following: Ni + 4 _________ Pb +2 _________

Lead (II) chloride _________ Iron (III) oxide _________ Check Point Write the formula: Lead (II) chloride _________ Iron (III) oxide _________ Copper(I) sulfite _________

Write the names of the following compounds: Check Point Write the names of the following compounds: FeBr2 _________ Fe2O3 _________ CuCl _________

Hydrates A hydrate is a compound in which there is a specific ratio of water to the ionic compound. Water molecules are chemically bonded to the ionic compound.

Hydrates Hygroscopic : A compound that easily absorbs water from the air. Deliquescent: A substance that is so hygroscopic that it takes up enough water from the air to dissolve completely and form a liquid solution.

Hydrates Anhydrous: A compound in which all of the water has been removed. Heating hydrates can remove the water in the compound. These compounds may become a different color than when it was a hydrate. TEXTBOOK PAGE 165

Hydrate Formula Because water is part of a hydrate (not just surrounding it) the formula is written in a special way. The name for the compound is written and then a “dot” is placed followed by the number of water molecules in the compound. The dot in the formula represents a ratio of compound formula units to water molecules.

Hydrate Formula To name a hydrate, first write the name of the regular compound. Then add a prefix to the word hydrate to indicate the number of water molecules present. Example : CuSO4•5H2O copper(II) sulfate pentahydrate

Hydrate Prefixes

Check Point Write the names of the following hydrates: BaCl2•2H2O _________ Na2CO3•H2O _________ Write the formula for the following hydrates: Calcium sulfate dihydrate _________ nickel(II) sulfate hexahydrate _________

Section 5.2 Covalent Compounds

Distillation A method of separating substances. A solid may be separated from a liquid. One liquid may be separated from another liquid.

Molecular Element A molecule that forms when atoms of the same element bond together. These atoms bond together to achieve stability.

Hydrogen Oxygen Nitrogen Cl (chlorine) Bromine Iodine Fluorine 7 Diatomic Molecules Hydrogen Oxygen Nitrogen Cl (chlorine) Bromine Iodine Fluorine H2 O2 N2 Cl2 Br2 I2 F2

Allotropes of Phosphorus Molecules of a single element that differ in crystalline or molecular structure. The properties of allotropes are usually different even though they contain the same element. Structure can be more important than composition in determining the properties of molecules. Allotropes of Phosphorus

Got Carbon? Organic Compound: Compounds that contain carbon. Inorganic Compound: Compounds that do not contain carbon.

Naming Covalent Compounds Write out the name of the first nonmetal. Write the name of the second nonmetal changing its ending to “ide”. Add a prefix to the name of each element to indicate how many atoms of each element are present.

Naming Covalent Compounds Write the element that is farther to the left in the periodic table first. If both elements are in the same group, name the element that is closer to the bottom of the table first. If there is only one atom of the first element listed , the prefix mono is omitted. If there are vowel combinations such as o-o or a-o next to each other in the name, the first vowel is omitted to simplify pronunciation. Example: mononitrogen monoxide

PREFIXES ARE ONLY USED WITH COVALENT COMPOUNDS (NOT IONICS)

Check Point Write the names of the following : CCl4 _________ N2O _________ Write the formula for the following : sulfur hexafluoride _________ tetraphosphorus decoxide _________

Common Acids TEXTBOOK PAGE 180

Naming Acids Acids Examples: Compounds that form H+ in water. Formulas usually begin with ‘H’. Examples: HCl (aq) – hydrochloric acid HNO3 – nitric acid H2SO4 – sulfuric acid www.chemistrygeek.com

Naming Acids “An easy way to remember which goes with which… No Oxygen w/Oxygen “An easy way to remember which goes with which… In the cafeteria, you ATE something ICky” www.chemistrygeek.com

Acid Nomenclature Flowchart www.chemistrygeek.com

Acid Nomenclature HBr (aq)  hydrobromic acid H2CO3 H2SO3  carbonic acid Has oxygen, -ate Has oxygen, -ite  sulfurous acid www.chemistrygeek.com

Naming Acids hydrofluoric acid sulfuric acid nitrous acid  H+ F- 2 elements  H+ F-  HF (aq) 3 elements, -ic  H+ SO42-  H2SO4 3 elements, -ous  H+ NO2-  HNO2 www.chemistrygeek.com

Check Point HI (aq) __________ HCl __________ H2SO3 __________ Name the following acids: HI (aq) __________ HCl __________ H2SO3 __________ HNO3 __________ www.chemistrygeek.com

Check Point Hydrobromic acid _______ Nitrous acid _______ Write the formula for the following acids: Hydrobromic acid _______ Nitrous acid _______ Carbonic acid _______ Phosphoric acid _______ www.chemistrygeek.com

Hydrocarbons TEXTBOOK PAGE 180