Ionic Nomenclature: 1. Binary: made-up of one monoatomic cation ion and one monoatomic anion. Metal...

Ionic Nomenclature:1. Binary: made-up of one monoatomic cation ion and one monoatomic anion. Metal (+) bond to Non-Metal (-)2. For binary acids, the cation is ALWAYS H+ . HBr3. Writing ‘Formula Units’

-Write the symbol of the element.-Assign oxidation numbers.-Criss Cross- Simplify

4. Naming Binary Ionic compounds- anion will end in –ide- first name is the name of the element.-second name is the name of the anion with the ending dropped

and –ide added. Calcium bromide- All cations other than Group 1A, 2A and Aluminum will have and Roman numeral to indicate the oxidation number of the that

metal. Iron (III) chloride

5. Binary acids; Hydro-anion root-ic acid. Hydrochloric acid.

6. Ternary Compounds: ionic compound in which at least one of the ions is a polyatomic ion.

7. For a ternary acid, the cation ion is ALWAYS H+ . H2SO4 .

-Naming ternary acids follows –ate,-ic , -ite, -ous

Sulfuric acid

8. Writing the ‘Formula Unit’ (Same 4 steps)-write the atom or polyatomic ion-assign the oxidation number-criss cross-simplify (more than one poly, put ( ) )

9. Naming ternary ionic compounds-first name is the name of the

element (or Ammonia if NH3).

-second name is the name of the polyatomic ion.

Cr(HSO4)3 Chromium bisulfate

10. Bases: Ionic compounds in which the anion is hydroxide, OH- (except NH3)

Ba(OH)2 Barium hydroxide

1. Cations are positive ions. Always written first.2. Anions are the negative ions. Written after the

cation3. Positive and negative ion pack in a regular pattern that balances the forces called an ionic crystal or crystal lattice.4. Lattice energy defines the strength of the ionic

bond. Large lattice energy = stronger bond5. Form 3-D compounds6. High melting and high boiling point.7. Compound defined by hardness and brittle.8. Almost always exothermic when bond is broken.

Energy-in to form the bond and energy-out when the bond is broken

9. Further separation on the periodic table, the MORE ionic characteristics. 10. Conductive current dissolved and molted state. Greater solubility = more ionic11. Ionic compounds are electrolytes = they carry an electric current when dissolved.12. Ionic compounds are referred to as formula units (FU).13. Net charge of the compound must = zero14. Greater ∆EN = greater ionic characteristic

UEQWhat are the unique characteristics of a

covalently bonded molecule?

LEQWhat is a covalent bond?

The joining of two or more elements through the sharing of valance electrons to form a molecule

Purpose: To form a stable octet between the elements

1. Covalent bonds are molecules (neutral) 2. Do not conduct electricity 3. Low melting and boiling points 4. Are less soluble in water and more soluble

in non-aqueous solvents.5. Can form multiple bonds. 6. Multiple bonds shorten bonding length and

increases bonding strength.7. Weak force of attraction between

molecules.

8. Elements close on the periodic tables tend to form covalent bonds.9. Metallic bonds are a type of covalent bond10. Hydrates bond covalently.

Atoms the share electrons form molecules. Molecules are expressed in ‘Molecular

Formulas’ Naming follows binary ionic naming trends

with prefixes to define the number of each atom in the molecule.

Hydrates follow binary naming with a prefix to identify the number of water molecules.◦ Molecular formulas are NOT simplified.

Prefixes:mono- for one (used w/ the second name

usually)di- for 2 hexa- for 6tri- for 3 hepta- for 7tetra- for 4 octa- for 8penta- for 5 nano- for 9deca- for 10

N2O5

Dinitrogen pentoxide

CCl4Carbon tetrachloride

Silicon dioxideSiO2

Diphosphorous hexaflourideP2F6

CuO . 5H2O

Copper (II) oxide pentahydrateNiCl3 . 2H2O

Nickle (III) chloride dihydrateChromium (II) sulfate heptahydrate

CrSO4 . 7 H2O

Barium sulfide trihydrateBaS . 3H2O

What is polarity and how is it applied to molecular bonding?

Non-Polar: equal sharing of the valance electrons.

Polar: unequal sharing of the valance electrons.

Polarity refers to the uneven sharing of valance electrons.

Electronegativity refers to the pull on another atoms valance electrons.

If the EN values are not the same then there is polarity (uneven pulling).

If the EN values are equal, then there is no polarity (even pulling) called non-polar

The closer the EN values the less polar.

Shape of molecule is symmetrical.

Homonuclear molecules.◦Diatomic molecules:

N2, O2, F2, Cl2, Br2, I2, and H2

Makes the #7

Shape of the molecules is asymmetrical due to unequal sharing of the electrons.

Heteronuclear: one nuclear charge is stronger than another.

Polarity is the function of the change in electronegativity (EN)◦ Increase EN, = more ionic chstc.

Rank these in decreasing covalent characteristics:

H2O, N2, NO3- , NaBr2, CO2

Solution:

1. Identify the electronegativity for each element in the molecule.2. Less covalent > 1.7 > more covalent.

N2 > NO3- > CO2 > H2O > NaBr2

Identify if the following is pure covalent, polar covalent or ionic: Use ∆EN

O3

N2O5

RbClN2

CCl4NH3

Cl2SO2

BaBr2

Pictorial representation of valance electrons.

Dot structure Stick structure

BCl3

CCl4

NF3

Representative elements share electrons to take on a Noble gas electron configuration.

Each element in a molecule will follow the octet rule.

Formula to determine the number of shared electrons:

N – A = S N = # of electrons needed to form a

Noble gas configuration. A = # of electrons available in the

valance. S = # of electrons shared

CS2

C2H4

CO32-

CHCl3

Sigma Bonds are the single electron overlap of the s orbital.

Forms single bonds, end-to-end. Pi Bonds are the overlap of the s and p

orbitals. Forms double and triple bonds w/ s end-

to-end and p side-to-side.

The joining together of two or more elements by the sharing of the valence electrons.The Lewis Structure: representation of the electrons in the valance of an atom. * Group A elements = the Group number is

the number of valance electrons.For Example: N C P ClShow the Lewis structure for the following.

PH3 CCl4 H2S SiH4

Covalent bonds are formed when valance electrons between two elements are share either by an end-to-end overlap relationship or an side-to-side overlap relationship.

1.Sigma bond (σ ): single covalent bond with a end-to-end relationship

BeCl2 CH4 AlF3 NH3

*sigma bonds are single bonds*bonding length is longer (Table 8.1)*bonding strength is less (Table 8.2)

pi bonds ( π ) : A side-to-side overlap of valance electrons. Forms multiple bonds.

CO2 O2 N2

*one sigma + one pi = double bond*one sigma + two pi = triple bond *double bond shorter bond length*double bond stronger bond*triple bond shortest bond length*triple bond strongest bond

CO2

N2

CS2

HNO3

NO31-

Which are polar? Which are non-polar? Which are non-polar with polar bonds?

Equally acceptable formulas. HNO3

NO31-

Most beryllium compounds Most Group IIIA elements Compound which require more than 8e-

in the valance. Compounds containing d or f transitional

elements ‘S’ with an odd number of electrons

CCl4 CO2

N2O5

N2O S3O5

NF3

Follows the rules as ionic compounds except prefixes are used to note ‘how many’.

Table 8-3, page 248.

VB Theory : Valance Bond Theory, orbital overlaps

VSEPR Theory: Valance Shell Electron Pair Repulsion Theory◦ Electrons arrange to max the distance between

electrons◦ Bonding pairs v. Unshared pairs

Linear (2) Trigonal Planar Tetrahedral Trigonal Pyramidal Angular (Bent) Trigonal Bipyramidal Octehedral

Formula AB2 w/ no unshared pairs VSEPR: bonding angle of 180o

VB: sp overlap Forms a polar bond and a non-polar

molecule.

Formula of AB3 and no unshared pairs. VSEPR: bonding angle of 120o

VB: SP2 overlap Polar bond w/ non-polar molecule

Formula of AB4 w/ no unshared pairs. VSEPR: bonding angle of 109.5o

VB: sp3 overlap Forms polar bonds and non-polar molecule.

Formula AB3 w/ one unshared pair on A. General: subtract 2.5o for each unshared

pair. VSEPR: bonding angle of 107o

VB: sp3 overlap w/ a polar bond and a polar molecule

Formula AB2 w/ 2 unshared pairs on A VSEPR: bonding angle of 104.5o

VB: sp3 overlap w/ polar bonds and polar molecule.

Formula AB w/ 3 unshared pairs VSEPR: bonding angle of 102o VB: sp3 overlap w/ polar bonds and polar

molecule.

Formula AB5 w/ no unshared pairs VSEPR: bonding angles at 90o, 120o and

180o

VB: sp3d overlap w/ polar bonds and polar molecule.

Formula AB6 w/ no unshared pairs VSEPR: bonding angles of 90o, 120o and

180o

VB: sp3d2 overlap w/ polar bonds and molecule

Molecule VB VSEPR Shape NI3PH3

CH4

SF6

H2S

PF5

BeCl2