Chemistry Bonds Ionic Bonding: electrostatic attraction. **Electron Configuration **Orbital Diagrams **Dot Diagrams **Periodic Trends

UEQ  How do chemist name and write ionic compounds?

LEQ  What properties and characteristics are unique to ionic compounds?

Evolution of a Topic Structure of the Atom atomic number = neutral atoms __________ and e - no mass mass number = where the mass of the n o = mass of the p + 16 S 32 And then:

Electron ArrangementOrbitalsDots S 16 Used the dot diagram to explain the gain (-) of electrons or the loss of electrons (+). And then:

Periodic Trends Atomic Radii: (distance between nuclei /2) Periods: Groups: Ionization Energy: the energy to remove an e - Periods: Groups: Electronegativity: attraction for another atoms e - EN trends = IE trends

Ionic Compounds Ionic compounds: electrostatic attraction between positive (+) ions called cations and negative (-) ions called anions. Two types of Ionic Compounds: 1. Binary Ionic Compounds: made-up of two mono-atomic ions, one (+) and one (-). 2. Ternary Ionic Compounds: made-up of at least one polyatomic ion (note reference)

Properties of Ionic Compounds  Cations are positive ions. Always written first.  Anions are the negative ions. Written after the cation  Positive and negative ion pack in a regular pattern that balances the forces called an ionic crystal or crystal lattice.  Form 3-D compounds  High melting and high boiling point.  Compound defined by hardness and brittle.  Almost always exothermic when bond is broken.  Lattice energy defines the strength of the ionic bond.

Properties of Ionic Compunds  Further separation on the periodic table, the MORE ionic characteristics.  Conductive current dissolved and molted state  Ionic compounds are referred to as formula units.  Net charge of the compound must = zero, Σ+ = Σ-

LEQ  How are ionic bonds formed?

Formation of Ionic Bonds Balance in the net charge: *Net charge must be ZERO. *Criss-Cross method to balance charge. **Write the symbol of the elements **Assigning oxidation numbers **Criss-Cross the numbers ONLY (these are the subscripts) **Simplify the subscripts to the smallest whole number **Roman numeral is the oxidation number of the cation *Metals or positive ion always written first. *An ionic compound is called a formula unit. *Binary : made up of two particles, + and -. *Ternary: made up of two particles, + and – in which one or both are polyatomic ions.

Formation of an Ionic Bond  Assign oxidation number. Review periodic trends:  Group 1A = 1+Group 2A = 2+Al = 3+  Oxygen 2-; Sulfur 2-Group 7A = 1-  Transitional Metal commonly = 2+  Transitional Metals use Roman Numeral to indicate +  Cu, Ag, Au commonly 1+ *******Criss-Cross Method******* The criss-cross method is used to ensure zero net charge.

Roman Numerals (for cations only) Iron (III) Lead (IV) Mercury (I) Tin (VI) Silver (II) Cr 4+ Hg 3+ Pb 5+

Also Names for Cations (Metals) Iron  Ferrous (Fe 2+ ) Ferric (Fe 3+ ) Copper  Cuprous (Cu 1+ ) Cupric (Cu 2+ ) Mercury  Mercurous (Hg 1+ ) Mercuric (Hg 2+ ) Lead  Plumbous (Pb 2+ ) Plumbic (Pb 4+ ) Tin  Stannous (Sn 2+ ) Stannic (Sn 4+ ) *******Criss-Cross Method******* The criss-cross method is used to ensure zero net charge.

Sample Compounds: 1. Use orbital diagrams to show how the following combine: Na and BrAl and SK and S 2. Now use the criss-cross method to show how the charges balanced in the above compounds. (positive ion always first).

Sample Compounds Fe (III)S Cr (IV)O MgO

Naming Binary Ionic Compounds  First name is the name of the cation (metal).  Second name is the name of the anion or non-metal with the ending dropped and the suffix –ide added.  You see –ide then = binary except for bisulfide, cyanide, hydroxide, ferrocyanide  NaClBaSCaBr 2

Naming Binary Ionic Compounds Fe 2 S 3 CuO AgCl Chromium (II) sulfide Nickle (III) Fluoride Tin (IV) oxide Li 2 S

LEQ  How can we write and name ternary ionic compound?

Polyatomic Ions Covalently bonded particles with a charge: **Table 7.9 or reference sheet. **Forms ionic compounds **Criss-Cross method, net charge is zero **Patterns in naming. **First name is the name of the element. **Second name is the name of the polyatomic ion. **More than one poly, put in parenthesis.

Writing Ternary Formula Units  Combination of at least one polyatomic ion.  Cation always written first followed by anion.  Net charge for formula unit must equal zero.  Only + polyatomic ion is ammonium, NH 4 +  More than one polyatomic ion must be in parenthesis.

Naming Ternary Ionic Compunds  First name is the name of the element or the polyatomic ion.  Second name If the anion is an monoatomic, then add –ide. If the anion is a polatomic ion, then the name is the name of the poly ion.

Writing Formula Unit from Name  Define if the name is of a binary or ternary compound. Binary anion ends in –ide.  Write the symbol for the element (metal first)  Assign oxidation numbers.  Criss-cross  Ensure that the net charge of the FU is zero  With transitional metal: The Roman numeral is the oxidation number for the metal.

Practice Problems  Write the formula unit for the following: a. potassium and iodide b. magnesium and chlorite c. aluminum and bromide d. cesium and nitrate e. barium and sulfite f. iron and oxide

Practice Problems Write the following ionic compounds: a. Iron (III) chromate b. Tin (IV) fluoride c. Copper (I) sulfate d. Lead (IV) oxide e. Mercury (II) bromide f. Iron (II) hydroxide

Oxyanion or Oxides Polyatomic ions that contain oxygens. Name based on the number of oxygens present. Chlorate ClO 3 - One less than –ate is –ite; chlorite ClO 2 - Two less than –ate is hypo- root-ite; hypochlorite ClO - One more than –ate is per-root-ate; perchlorate ClO 4 - ****The charge NEVER changed*****

Sample Compounds Write the compound for the following ions: Al to SO 4 NH 4 to PO 4 Mg to NO 3 Al 2 (SO 4 ) 3 (NH 4 ) 3 PO 4 Mg(NO 3 ) 2

Writing Formula Unit from Ternary Name  Identify if the name is of a binary or ternary compound. Ternary anion ends in –ite or –ate.  Note exception of hydroxide, cyanide, bisulfide.  Write the symbol of the elements and/or polyatomic ion  Assign the oxidation number.  Criss cross  More than one poly put parenthesis  Assure the net charge is zero.

Naming Ionic Compounds Binary Ionic Compounds: Single cation to anion. NaClK 2 SMgO Ternary Ionic Compounds: Combination of anions and cation along with polyatomic ions. K 2 SO 4 NaHCO 3 (NH 4 ) 2 SO 4

LEQ  How are acids and bases identified and written?

Writing and Naming Acids/Bases  Binary Acids Hydrogen is the cation and is always written first. Balance charge to = zero. The –ide on the anion is dropped and –ic is added. Hydro – root of the anion – ic acid. Anions of binary acid are 7A elements, along with oxygen and sulfur

Writing and Naming Binary Acids  HCl H2SH2S  Hydrofluoric acid  Hydrobromic acid  HI

Writing and Naming Acids/Bases  Ternary Hydrogen is the cation and always written first. Followed by a polyatomic ion. NO Hydro- prefix. Poly name follows; -ate –ic ; -ite –ous

Writing and Naming Ternary Acids  H 3 PO 4  H 2 SO 3  HClO 3  Nitric acid  Sulfuric acid  HNO 2  HC 2 H 3 O 2  Perchloric acid

Writing and Naming Acids/Bases  Bases NH 3, ammonia, only base not identified by hydroxide, OH. Identify by the OH anion First name is the name of the element. Second name is hydroxide Metals other than Group IA and Group IIA have the oxidation number indicated with Roman numeral.

Writing and Naming Bases  NaOH  Barium hydroxide  LiOH  Iron (III) hydroxide  Ca(OH) 2  CuOH  Chromium (IV) hydroxide

LEQ  What does the word ‘hydrate’ mean to you?

Hydrated Compounds Hydrated compounds are ionic compounds that has water molecules covalently bonded (shared). 1. The water molecule is a part of the chemical substance. 2. The water does contribute to the mass of the compound. 3. Written as CuSO 4. 5 H 2 O for Copper (II) sulfate with 5 water molecules attached.

Hydrated Compounds 4. The dot DOES NOT mean to multiply. 5. The number of water molecules is denoted using prefixes.

Molecular Formulas Prefixes: mono- for one (used w/ the second name usually) di- for 2hexa- for 6 tri- for 3hepta- for 7 tetra- for 4octa- for 8 penta- for 5nano- for 9 deca- for 10

Examples MgSO 4. 8H 2 O Use ionic nomenclature to name the compound and them the prefix for ‘8’ followed by ‘hydrate’. Magnesium sulfate octahydrate NiClO 3. 5H 2 O Nickel (I) chlorate pentahydrate Barium chloride dihyrate BaCl 2. 2H 2 O

Sampler Fe(NO 3 ) 2. H 2 O Iron (II) nitrate monohydrate Calcium bicarbonate heptahydrate Ca(HCO 3 ) 2. 7 H 2 O KMnO H 2 O Potassium permanganate decahydrate Lead (I) oxide pentahydrate Pb 2 O. 4H 2 O

LEQ  How are molecules different compared to ionic formula units?

Compare Ionic Cpd to Molecules Ionic Formula UnitsMolecules *bonded charged particles*no charges (polar) *transfer electrons*electrons shared *ionic bonds*covalent bonds *metal-nonmetal*nonmetal-nonmetal *conductive*non-conductive *brittle, crystal lattice*malleable *solid or solutions*liquids or gases

Metallic Bonds/Properties  Metallic bonds, electrons are shared between metal atoms.  Free electron called delocalized electrons.  Sharing make metallic bonds: Flexible DuctileMalleable High melting pointHigh boiling point Good conductors of heat and energy

Molecular Formulas Bonding of element with a small difference in electronegativity. ***Usually non-metal bonded to non-metal*** Writing and naming: 1. Use of prefixes to indicate the number of each element in the molecule. 2. Follow the same standards as in the naming of formula units.

LEQ  What are the characteristics in naming molecular formulas?

Molecular Formulas Prefixes: mono- for one (used w/ the second name usually) di- for 2hexa- for 6 tri- for 3hepta- for 7 tetra- for 4octa- for 8 penta- for 5nano- for 9 deca- for 10

Molecular Nomenclature PCl 5 Phosphorous pentachloride NOTE: One species for the first element does not start with mono- N 2 O Dinitrogen monoxide NOTE: Second species of one element will include mono-

Molecular Formulas N2O5N2O5 Dinitrogen pentoxide CCl 4 Carbon tetrachloride Silicon dioxide SiO 2 Diphosphorous hexafluoride P2F6P2F6