Presentation on theme: "Ch 5 & 6: Bonding, Formulas and Naming Notes. Types of Chemical Bonds: A. Ionic Bonding negatively 1) Positively charged ions are attracted to negatively."— Presentation transcript:
Ch 5 & 6: Bonding, Formulas and Naming Notes
Types of Chemical Bonds: A. Ionic Bonding negatively 1) Positively charged ions are attracted to negatively neutral charged ions, making a neutral compound. 2) Properties of Ionic Compounds: melting poin ts a) high melting poin ts. solutions conductorselectrolyte s b) dissolve in water to form solutions that are good conductors of electricity (electrolyte s ). electronegativity c) have a large electronegativity difference between elements. metalsnonmetals d) usually form between metals and nonmetals.
3) The Octet Rule: fullvalencestable octet a)Atoms tend to gain or lose electrons in order to acquire a full set of valence electrons (stable octet). transfer valence b) Atoms will transfer electrons (e - ) to each other in order to have a full set of valence electrons. ionic c) When electrons are transferred, ionic bonds are formed.
Ions Atoms can form ions by gaining or losing electrons. – Metals tend to lose one or more electrons to form positive ions called cations. –Cations are generally named by using the name of the parent atom.
Nonmetals tend to gain one or more electrons to form negative ions called anions. Ions Anions are named by using the root of the atom name followed by the suffix –ide.
Ionic Bond Practice Tutorial
4) Types of Compounds: a) Binary form from monatomic ions – have 1 cation and 1 anion. Ex) Mg +2 O -2 Ca +2 Cl -1 MgO CaCl 2
Na +1 O Not Balanced 2 + (- 2) = 0 Balanced Na 2 O 2 x +1 = +2 1 x -2 = -2
Al +3 O -2 Al +3 O Not Balanced (- 6) = 0 Balanced Al 2 O 3 2 x +3 = +6 3 x -2 = -6
4) Types of Compounds: covalently single b) Tertiary form from polyatomic ions which consists of a group of atoms covalently bonded with a single charge that bond ionically with other ions. Ex. “ammonium sulfate”, NH 4 +1 SO 4 -2 (NH 4 ) 2 SO 4
Name this compound: FeO If that’s correct, name this: Fe 2 O 3 How can we distinguish between these compounds? What is the charge on the oxygen in each compound? Then what is the charge on the iron in each compound? Fix the name of the first compound: Iron oxide Iron (II) oxide Iron (III) oxide Fe +2 O -2 Fe +3 O -2 X
Ions Ion Charges and the Periodic Table
5) Polyvalent Metals: transition octet roman numerals Some metals including the transition metals do not follow the octet rule and may form more than 1 kind of cation. These ions are named with roman numerals to distinguish between them. Ex) Fe +2 iron (II) read “iron two” Fe +3 iron (III) read “iron three” FeCl 2 iron (II) chloride FeCl 3 iron (III) chloride Copper (I) sulfate Copper (II) phosphate Cu 2 SO 4 Cu 3 (PO 4 ) 2
6) Lewis Dot Diagrams for elements: Element# of val. ElectronsDot Diagram Li 1 Li N 5 Be 2 F 7 Ne 8 Au 2 C 4
B. Covalent Bonding sharing 1) Covalent Bonds are formed by sharing pairs of electrons between 2 atoms. nonmetals low 2) Usually formed between two nonmetals with a low electronegativity difference. 3) Molecules : covalent a) a group of atoms held together by covalent bonds molecules b) molecular substance – contains molecules
4) Naming : a)uses prefixes: 1 mono- 4 tetra- 7 hepta- 10 deca- 2 di- 5 penta-8 octa- 3 tri- 6 hexa-9 nona- b) end in “ ide ” last c) More electronegative element is written last one d) Only use a prefix on the first element if it is more than one. secondelement e) Always use a prefix for the second element. dihydrogen monoxide Ex) water H 2 O dihydrogen monoxide nitrogen dioxide smog NO 2 nitrogen dioxide
5) Types of formulas for covalent bonding many compound a) Molecular Formula shows how many atoms make up a compound. CH 4 H 2 O ex. CH 4 & H 2 O bonded b) Structural Formula shows how the atoms are bonded to each other. ex.
dots 1. Uses 2 dots to show an unshared pair of electrons electrons. dashes 2. Uses dashes to represent covalent bonds (a shared pair of electrons) in a structural formula. octet 3. The octet rule should be satisfied for each element in the compound. lowest ratio c) Empirical Formula is the lowest whole number ratio of all the elements in the compound. Ex) C 6 H 6 =CH C 6 H 12 O 6 =CH 2 O
6) Multiple Bonds – can be used to satisfy the octet rule 1 Single Bonds – Share 1 pair of electrons. Ex) methane or phosphorous trichloride
2 Double Bonds – Share 2 pairs of electrons. Ex) formaldehyde, CH 2 O
3 Triple Bonds – Share 3 pairs of electrons strongest (strongest bond). Ex) ethyne, C 2 H 2
8) Properties of Covalent Bonds meltingbrittleodor conductors a) Low melting points, brittle, strong odor, poor conductors of electricity. large uneven b) Polar Bonds – form between elements with large differences in electronegativity. These have an uneven sharing of electrons. Ex) water partial negative side partial positive side
equalpull c) Nonpolar bonds – exert equal pull on the electrons. Ex) O 2
9) Electronegativity Chart is used to determine bond type non polar covalent polar covalent ionic bonds even sharing - no charge O 2 Ex) O 2 uneven sharing – slight charge on molecule H 2 O Ex) H 2 O electrons transferred – forms ions NaCl Ex) NaCl
Types of Bonds
C. Ionic & Covalent Bonds Summary: Ionic BondingCovalent Bonding metal-nonmetalnonmetal-nonmetal e - transferrede - shared large electronegativity difference (>1.9) electronegativity difference (0 1.9) ions formedno ions written cation (+) anion (-) more electronegative element written last name cation - name anionuse # prefixes/ends in ide forms ionic compound (formula unit) in a crystal lattice forms molecules Written with a chemical or empirical formula Written with a molecular or structural formula NaCl – sodium chlorideCCl 4 – carbon tetrachloride
[Na + ] [ - ] How Atoms Bond Video Clip
D. Acids: H ions anion 1) A molecular compound that dissolves in water to produce H ions and a characteristic anion. ionic 2) In water, acids behave like ionic compounds. H COOH 3) Most acid formulas begin with H. (Except organic acids) “ COOH ” charge 4) The number of hydrogens in the formula depends upon the charge of the anion.
5) Types of Acids carboxylic a.) Organic Acids contain the carboxylic group, -COOH or CH 3 COOH acetic acid (vinegar) Ex) CH 3 COOH acetic acid (vinegar) (or HC 2 H 3 O 2 ) (or HC 2 H 3 O 2 )
hydrogenanion b.) Binary Acids contain hydrogen and 1 type of anion. A two-word name is used for binary acids. 1st word: prefix is “ hydro ” root is formed from the anion anion suffix “ ide ” is changed to “ ic ” 2nd word: is “acid” Ex) HCl anion is chloride hydrochloric acid Prefix root suffix hydrobromic acid HBr anion is bromide hydrobromic acid hydrophosphoric acid H 3 P anion phosphide hydrophosphoric acid
oxygen c.) Oxo (Tertiary) Acids : contain oxygen within a polyatomic ion. A two-word name is used for oxo acids. H 2 SO 4 sulf ate sulfur ic acid H 2 SO 3 sulf ite sulfur ous acid sulfur or phosphor (to sound better) 2nd word is “acid” If you “ ate ” something you don’t like, you say “ ic ” “ ite-ous ”
HNO 3 anion is nitr ate nitric acid root suffix H 3 PO 3 anion is phosph ite phosphor ous acid Nitrous acid, anion is nitr ite formula is: HNO 2 Phosphoric acid, anion is phosph ate formula is: H 3 PO 4
E. Hydrates: 1.) Ionic compounds that absorb H 2 O into their solid structures. magnesium sulfate heptahydrate Ex) magnesium sulfate heptahydrate ( epsom salt ) Formula: MgSO 4 7H 2 O substance without water MgSO 4 2.) Anhydrous substance – substance without water MgSO 4 copper (II) sulfate pentahydrate Ex) CuSO 4 5H 2 O copper (II) sulfate pentahydrate (bright blue) CuSO 4 – anhydrate (light blue/white)