Topic 2.1-2.3 Quiz Review

Lewis Dot Structures

Based off of their electron pairing in orbitials (config)

• Ionic Lewis Structure: Show the charge and no valence electrons on cation; on anion, octet, brackets, and then charge

• Covalent: Show the connections between the atoms and lone pairs

coordinate covalent bonds

1 nonmetal atom contributes both e- in bonded pair

Covalent: Polar v. Nonpolar; dipole moments?

• From most to least but really high EN: FONCl

• Dipole moment: partial negative and positive charges

• dif. EN less 0.5 = covalent nonpolar, .5 to 1.7 polar, higher 1.7 ionic

Covalent Characteristics and Metallic Character

• No luser; brittle (hard or soft)

• Poor conductors, oxides acidic

• Anions

• Nonmetallic higher as up right; metallic higher as down left

Ionic

• Crystal

• High melt/boil

• Hard/brittle

• Conductors when dissolved/melted; insulate as solid

Metallic Bonding

• Between alloys/metals; together by sea of electrons. Represented like lattice but electrons

• Luster

• Malleable/ductile

• Conductors

Bond Length

• Distance btwn nuclei; decrease PE (by bonding), if too close high PE as nuclear repulsion

• Form bond resulting in lowest PE possible

• On a graph, peak is when too close (HIGHEST PE), min is the bonding distance, and convergence is when far away

  • Minimum higher is less PE

What affects bond length in covalent compounds?

• H2 has the SHORTEST bond length

• Triple bonds are shorter than double bonds which are shorter than single bonds

• Atoms with small atomic radius form shorter bonds

What affects bond length in ionic compounds?

• the difference is charges - the larger the charges, the shorter the bond length

• If charges are the same, use the atomic radius - smaller ions form shorter bonds

Bond Energy

• Breaking bonds is endothermic (gain in energy); forming exothermic (neg)

• Breaking shorter bonds needs more energy; forming short bonds releases more energy

Bond Order

• Average dividing number of bond lines by locations of bond

• Larger = longer

Crystal Lattice

Alternating pos/neg ions ionic compounds

• Have higher melting points, hardness, vs aother bonds

Lattic Energy

• Bond energy of ionic compound; can be given as enthalpy (energy used to forming the lattice; negative because forming bonds)

• Draw diagrams based on the size of particles - remember loss/gain electrons!

Lattice Bond Strength and Why are Metals Good Conductors?

• Lattice Bond Strength higher with shorter bond

• Metals are good conductors - decentral electrons conduct energy