Chapter 7: Ionic and Metallic BondingChapter 9: Naming Compounds and

Writing Formulas

Electron Configuration Exceptions P. 136

Cr – [Ar] 4s2 3d4 - does not occur

Cr – [Ar] 4s1 3d5 – occurs

Why? • Greater stability is achieved with half filled

3d5 orbitals.

Another example:

Cu – [Ar] 4s2 3d9 - does not occur

Cu – [Ar] 4s1 3d10 – occurs

Why? • Greater stability is achieved with

completely filled 3d10 orbitals.

Other Exceptions that follow this pattern:

Ag, Au

P. 208 - Q - 58 and 59

Valence Electrons Dictate Chemical Properties

• Representative Elements – look at the Group #

• Symbolically represented by Electron Dot Structures

P. 193 - #8

Remember Stability

• Octet Rule – atoms want to obtain a noble gas electron configuration

• ns2 np6

• Metals – lose electrons to gain the octet of the next lowest energy level– Cations

• Non-Metals – gain electrons to obtain a complete octet– Anions

Cation Formation

K 1s2 2s2 2p6 3s2 3p6 4s1 reactive

Metals – lose electrons to gain the octet of the next lowest energy level

K 1s2 2s2 2p6 3s2 3p6 unreactive

K K+1 + e-

Cations – lose electrons

Transition Metals: Pseudo Noble Gas Configurations

Ag - 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 4d10 5s1

Options – lose 11 electrons or gain 7

Neither happens

Ag loses 1 electron to gain a pseudo noble gas configuration

Ag1+ - 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 4d10

Transition Metals – Why Multiple Charges?

Fe - 1s2 2s2 2p6 3s2 3p6 4s2 3d6

Can become Fe2+ or Fe3+

Fe2+ Fe3+

loses the 4s2 electron s loses the 4s2 electrons and one 3d electron

Creates 5 half filled 3d orbitals

Anion Formation

Cl 1s2 2s2 2p6 3s2 3p5 reactive

Non Metals – gain electrons to complete their octet

Cl1- 1s2 2s2 2p6 3s2 3p6 unreactive

Cl + e- Cl 1-

A Halide

Anions – end in -ide

• Gain electrons

Ionic Bonds form Ionic Compounds

• Electrostatic attraction of cations and anions

• Neutral compounds • Binary compounds – MgO, not CaSO4

Ionic Bonds

Ionic Bonds

P. 208 - Q - 66

Practice

• Show how the following form ionic compounds.– Electron configuration, orbital diagram and electron dot

diagrams

1. 3 Sodium atoms and one Nitrogen Atom2. 2 Lithium atoms and one Oxygen Atom3. 1 Strontium atom and 2 Fluorine Atoms

P. 196 - Q - 12 and 13

Ionic Compounds

• Chemical Formula – the type and number of atoms in smallest representative unit of a substance

• Formula unit – the lowest whole number ratio of ions in an “ionic compound”

Naming Ions

• Monatomic Ions – a single atom with a charge– Cations - K1+, Ca2+

– Anions – O2-, N3-

• Drop the ending and add –ide

• Polyatomic ions – charged ions containing more than one atom

Polyatomic Ions

• Most end in -ate or -ite• NO3

- Nitrate NO2- Nitrite

• SO42- Sulfate SO3

2- Sulfite

• more oxygen atoms - suffix –ate• fewer oxygen atoms - suffix -ite

Bonding Nomenclature – Naming Ionic Compounds and Binary Molecular Compounds

Are they a metal and a non-metal or a metal and a polyatomic ion?

Are they 2 non-metals?

Does the cation have one oxidation number?

Does the cation have multiple

oxidation numbers?

State the name of the cation.

State the name of the anion. Drop the ending and add –ide. Do not change if it is a

polyatomic ion.

State the name of the cation.

State the name of the anion. Drop the ending and add –ide. Do not change if it is a

polyatomic ion.

State the oxidation number of the cation in Roman

numerals. Use the anion to determine the charge.

State the name of the 1st element.

State the name of the 2nd element. Drop the ending and

add –ide.

Add prefixes to identify the number of each element

1 – mono* 6 – hexa2 – di 7- hepta3 – tri 8 - octa4 – tetra 9 - nona5- penta 10- deca

* used only on the 2nd element

Ionic Compound Binary Molecular Compound

Ex. Na1+ Ex. Fe2+ or Fe3+

Ex. Sodium Ex. Iron

Ex. Sodium Bromide Ex. Sulfate

Ex. Iron (III) Sulfate Ex. Dicarbon Hexafluoride

Fe ( ) SO42-

Fe ( ) SO42-

SO42-

Fe must be 3+ because there are 2 Fe ions and the sulfate ions have a 6- charge.

NaBr, Fe2(SO4)3, C2H6

Bonding Nomenclature – Writing Formulas for Ionic Compounds and Binary Molecular Compounds

Are they a metal and a non-metal or a metal and a polyatomic ion?

Are they 2 non-metals?

Write the symbol of the cation and the anion.

Assign charges to each. Remember that roman numerals apply to the cation.

Are they balanced? Rewrite the symbols without the charges.

Rewrite the symbols and symplify the crossed charges. Do not write

the crossed charge if it was a 1.

Write the symbol of each element.

Each prefix identifies the quantity of each element.

Write the number as a subscript for each

corresponding prefix.

1 – mono* 6 – hexa2 – di 7- hepta3 – tri 8 - octa4 – tetra 9 - nona5- penta 10- deca

* used only on the 2nd element

Ionic Compound Binary Molecular Compound

No

Cross the charges.

yes

Properties of Ionic Compounds

• Depend on attraction of bonded elements• Na and Cl

– + surrounded by –– - surrounded by +

• Forms a crystal lattice– Size and number of ions

determine the shape

Properties - continued

• Melting and boiling points and hardness– Depend on attraction of ions– Greater attraction = ↑MP, BP and hardness

Mg 2+ O2-

Greater attraction

Continued

• Non conductor of electricity– Ions are static

• Conduct electricity when in water or melted– Ions free to move– Called electrolytes when dissolved in water

Exothermic nature

• Ionic compounds release energy upon formation because they are becoming more stable

Does the size of the ion influence the lattice energy?

Does the charge of the ion influence the lattice energy?

Lattice Energy - energy needed to separate one mole of ions

Lattice energy

• energy needed to separate one mole of ions – Depends on size of ions– Smaller the ion the greater the attraction

– Proximity to the nucleus

– Depends on the charge of the ion• Greater the charge the greater the attraction

P. 199 Q - 22

Metallic Bonds

Electron Sea Model

• Atoms outer energy levels overlap

• Electrons move freely from atom to atom (delocalized electrons, s and d electrons)

• Cations are formed

• Metallic bond forms when delocalized electrons are attracted to the metallic cations

P. 203 - Q - 23

Aufbau Diagram

Equal energies – 2 p

Sublevels have different energy levels

Energy levels overlap

Properties of Metals Explained

Mobile cations and electrons

• Moderate melting pts. extreme boiling pts.

• malleable and ductile

Strong Attraction for each other• durabilityMobile electrons• good conductors of heat and electricity Interaction with photons of light• lusterAmount of delocalized electrons• ↑electrons ↑strength and hardness• s block weak, d block hard

P. 203 – 26, 27 - P. 207 - Q – 46, 47, 48, 51

Alloys – mixture of 2 or more elements that have metallic properties superior to their parent element

Types of Alloys – Tech and Society (Page 204-205)

• Substitutional – similar size elements are substituted with one another– Stainless steel, pewter, gold

• Interstitial – extremely small atoms fill in the holes between much larger atoms

• Properties become more desirable– Carbon-steel – much harder, stronger, less ductile

than iron alone, corrosion resistant

P. 203 - Q - 25