Molecular Bonding

Question 1

Define and Describe

Ionic Bonding

Answer 1

Involves a metal and nonmetal
- Involves the transfer of electrons
- Forms extended structures (not molecular)
- Compounds are hard, rigid, and brittle
- Poor conductors in the solid state
- Good conductors in the liquid or aqueous states
- Held together by elecrtostatic forces (Lattice Energy)

Question 2

Define

Lattice Energy

Answer 2

The energy that is released when gaseous ions bond to form the ionic solid

Porportional to the electrostatic force

L.E. = (q1q2)/d^2

Question 3

Define and Describe

Covalent Bonding

Answer 3

Bonding between a metal and nonmetal
- involves the sharing of electrons
- Forms compounds with molecular stucture as well as extended structure
- Molecular compounds tend be gases or liquids with low melting or boiling points

Question 4

Whats the difference between pure covalent bonds and plar covalent bonds

Answer 4

Pure covalent bonds share the electron evenly
- They’re usally homonuclear diatomic molecules

Polar covalent bonds have uneven shareing of the electron
- They tend to be stronger

Question 5

Whats the difference between elecronegativity and electon affinity?

Answer 5

Electronegativity - The ability of an atom to attract shared e- in a bond

Electron Affinity - When an atom/ion adds a e- in the gaseous state

Question 6

Electronegativity

Answer 6

Electronegativity - The ability of an atom to attract shared e- in a bond

Question 7

Electron Affinity

Answer 7

Electron Affinity - When an atom/ion adds a e- in the gaseous state

Question 8

What makes the ionic character of a covalent bond stronger

Answer 8

A larger difference in electronegativities

Question 9

Define and describe

Metallic Bonding

Answer 9

Bonding between a metal and a metal
- Has an extended strucute in a “sea” of delocalized electrons
- metals are malleable and ductile
- Good conductors
- Moderatly high melting and boiling points

Question 10

What are the exeptions to the octect rule?

Answer 10

1. Espanded valence shells
   - Elements in period 3 and beyound can do this (availible d orbitals)
2. Incomplete octets
   - Berylium, Boron, Alluminum may have less than 8 electrons
3. Odd electron species
   - Put the unpaired electron on the least electronegative atom

Question 11

Define

Formal Charge

Answer 11

The difference between the number of valence electrons in the free atom and the number fo electrons assigned to the atom in a molecule

Formal Charge = (valence electrons) - (lone pair elecrons) - 1/2(electrons in covalent pairs)

Question 12

Which atom should you never bond in a lewis diagram

Answer 12

Flurine

Question 13

What is a resonance structure

Answer 13

When you can draw more than one lewis diagram

Question 14

Rules of Formal Charges

Answer 14

1. Try to make the F.C. = 0 (this is the most stable)
2. Low formal charges are prefered
3. • F.C. is prefered on less electronegative atoms, - F.C. is prefered on less electronegative atoms
4. Like charges must be seperated

Question 15

Valence Bond Theory

Answer 15

A covelent bond is formed the atomic orbitals overlap and a pair of electrons is localized in the region between the atoms

Question 16

What is a sigma bond?

Answer 16

End to end overlap of obitals
- Often hybridized orbitals

Question 17

What is a pi bond?

Answer 17

Side by side overlap of unhybridized orbitals

Question 18

How many sigma bonds can an atom form with one other atom?

Answer 18

Only one

Question 19

What creats covalent bond strength?

Answer 19

Length and energy

Can be calculated by:
△H = (Sum of bonds broken) - (sum of bonds formed)

Multiple bonds are shorter, therfore stronger

Question 20

Molecular Orbital Theory

Answer 20

Electrons from atomic orbitals combine to form a single molecular orbital

This is not considered a bond
- DO NOT COMBINE WITH VESPR