Chemical BondingChemical Bonding

By the end of this lesson you will be able to: Name and describe the 3 types of

bonds and how they are different List possible compounds in each

and how elements are affected by the bonds they share

Describe how we know these bonds exist. What are properties of the bonds?

Ionic BondsIonic Bonds

Bond most often between a metal Bond most often between a metal and a nonmetaland a nonmetal

Transfer Transfer of electrons from the of electrons from the metalmetal to the to the nonmetalnonmetal

Electrical attraction between large Electrical attraction between large numbers of cations and anions numbers of cations and anions called clusterscalled clusters

Ion = a charged particleIon = a charged particle

Ionic BondsIonic Bonds

Cation = Cation = + charged+ charged particle particle– Loves to give Loves to give electronselectrons away away– LowLow Ionization Energy, Electron Ionization Energy, Electron

Affinity & ElectronegativityAffinity & Electronegativity– Typically are Typically are metalsmetals– Most metallic element = Most metallic element = FrFr

Ionic Bonds (cont.)Ionic Bonds (cont.)

Anion = Anion = - charged- charged particle particle– Loves to Loves to acceptaccept electrons electrons– HighHigh Ionization Energy, Electron Ionization Energy, Electron

Affinity & ElectronegativityAffinity & Electronegativity– Typically are Typically are nonmetalsnonmetals– Most nonmetallic element = Most nonmetallic element = FF

Ionic Bonds (cont.)Ionic Bonds (cont.)

If a bond is ionic:If a bond is ionic:– The compound is The compound is solidsolid– The compound will fall apart The compound will fall apart

((dissociatedissociate) into its original ions ) into its original ions when dissolved in waterwhen dissolved in water

-If a conductivity test is performed, -If a conductivity test is performed, the light bulb will…the light bulb will…

light!light!

--EN values 1.8 up to 4EN values 1.8 up to 4

In General

Ionic Bonds are the strongest bonds there are

Covalent BondsCovalent Bonds

Formed when 2 Formed when 2 nonmetalnonmetal atoms atoms shareshare electrons electrons

Can be liquid, solid or gasCan be liquid, solid or gas

Polar Covalent Polar Covalent BondsBonds

Unequal Unequal sharing of electronssharing of electrons Electrons attracted more to higher E.N. Electrons attracted more to higher E.N.

atomatom Electronegativity difference range = Electronegativity difference range = 0.3 0.3

– 1.7– 1.7 (for polar covalent bonds) (for polar covalent bonds) Polar Covalent Bonds dissolve in Polar Covalent Bonds dissolve in waterwater

– Why?Why?– (Check out page 19 in your packet for EN of water)(Check out page 19 in your packet for EN of water)

The light bulb The light bulb doesn’t light updoesn’t light up..

Non-polarNon-polar Covalent Covalent BondsBonds

EqualEqual sharing of electrons sharing of electrons Electronegativity difference range Electronegativity difference range

= = 0.0 – <0.30.0 – <0.3 Usually found between diatomic Usually found between diatomic

molecules – two of the same molecules – two of the same atomsatoms

Non-polar covalent bonds don’t Non-polar covalent bonds don’t dissolve in water.dissolve in water.

Metallic BondsMetallic Bonds

Bond formed between 2 Bond formed between 2 metalmetal atoms.atoms.

Excellent electrical conductors in Excellent electrical conductors in solid statesolid state

Electrons are free to move within Electrons are free to move within electron clouds of all metal ions = electron clouds of all metal ions =

Sea of ElectronsSea of Electrons

Metallic Bonds

In metals, p-orbitals In metals, p-orbitals and some d-orbitals and some d-orbitals are completely are completely vacant and overlap vacant and overlap each atom.each atom.

Electrons are Electrons are delocalizeddelocalized – they – they don’t belong to any don’t belong to any one atom anymore.one atom anymore.

Quick Review

Ionic bonds are between– A) metals and non-metals– B) non-metals– C) metals

Answer A) metals and non-metals

Quick Review

Covalent bonds are between– A) metals and non-metals– B) non-metals– C) metals

Answer B) non-metals

Quick Review

Metallic bonds are between– A) metals and non-metals– B) non-metals– C) metals

Answer C) metals

Quick Review

The strongest bonds are between– A) metals and non-metals– B) non-metals– C) metals

Answer A) metals and non-metals (ionic)

Quick Review

Ionic bonds at room temperature are– A) solid– B) liquid– C) gas– D) any

Answer A) solid Can you name some?

Quick Review Covalent bonds at room temperature are

– A) solid– B) liquid– C) gas– D) any

Answer D) any Can you name some? HCl (aq), Bromine (aq), Fluorine (g),

Diamond (s)

Quick Review Metallic bonds at room temperature are

– A) solid– B) liquid– C) gas– D) any

Answer A) solid and B) liquid What metallic bonds can be liquid at room

temperature? Hg Any ideas why? Bond strength not enough to make a solid

yet strong enough to keep it from being a gas.

Quick Review

Which bonds are most likely to dissociate in water (water is polar)– A) ionic– B) polar covalent– C) nonpolar covalent– D) Metallic

Answer A) ionic

Piecing It All Together

The type of bond can be predicted by subtracting electronegativity values.– Nonpolar or polar?Difference Bond Type

X ≤ 0.3 Non-Polar Covalent

0.3 ≤ X ≤ 1.7 Polar Covalent

X ≥ 1.7 Ionic

Where to get the values?

2323

Use the electronegativity difference to identify the type of bond between the following:

nonpolar covalent (NP), polar covalent (P), or

ionic (I).

A. K-N

B. N-O

C. Cl-Cl

D. H-Cl

Learning Check

2424

Use the electronegativity difference to identify the type of bond between the following:nonpolar covalent (NP), polar covalent (P), or

ionic (I).

A. K-N 2.2 ionic (I) B. N-O 0.5 polar covalent (P)

C. Cl-Cl 0.0 nonpolar covalent (NP) D. H-Cl 0.9 polar covalent (P)

Solution

Hydrogen Bonds

Intermolecular – attraction between molecules

One molecule is polar and has Hydrogen in a H-F, H-O or H-N bond

Other molecule has an unshared pair of electrons, usually F, O, N

Hydrogen Bond Example:

Van der Waals Bonds

These bonds are important for Noble

Gases Very weak bonds Electrons of Noble Gases get

shifted to one side causing it to attract a slightly positive atom that is nearby.

Van der Waals Bond Example: