Chapter 3- Bonding Flashcards
Incomplete octet
Exception to octet rule, where element is stable with less than 8 valence electrons.
H, He, Li -2
Be -4
B -6
Expanded octet
Any element in period three can hold more than 8 electrons but optimizing their d subshell.
Odd # electrons
Compounds with odd number of electrons cannot distribute electrons to have eight on each element.
Ionic bond
Is formed via the transfer of one or more electrons from an element of relatively low IE (ionization energy). To an element of high electron affinity.
Occur btw elements with large differences in their electronegativities. 🔼EN > 1.7
Cation
Positively charged ion
Anion
Negatively charged ion.
Crystalline lattices
Large organized arrays of ions which form in ionic compounds in solid state.
Covalent bonds
Formed via the sharing of electrons bye two elements of similar electronegativities.
Bond order
Refers to whether a bond is single/double/triple.
Bond order increases as…
Bond strength increases.
Bond length decreases.
Bond energy increases.
Nonpolar bond
Results in molecules which both have relatively similar electronegativities. Equal sharing of electrons. 🔼EN
Polar bond
When a significant difference in electronegativities to cause unequal sharing. 🔼EN 0.5-1.7
Coordinate covalent
Results when a single atom provides both bonding electrons while the other atom does not contribute any.
Most often occurs in acid-base reactions.
Acid gives H+, base accepts H+
Formal charge
=V - B/2 -NB
VSEPR
Predicts the 3-D molecular geometry of covalently bonded molecules.
Electronic vs. Molecular geometry
Sigma bonds
Are result of head to head overlap
Pi bonds
Are the result of the overlap of two parallel cloud densities.
Intermolecular forces
Are electrostatic attractions between molecules.
Significantly weaker than covalent bonds.
London dispersion forces.
Weakest.
Vander wall force.
As size of atom or structure increases so does these forces.
Geico
Dipole-dipole forces
Evident in solid and liquid phases, but negligible in gas phase due to distance of particles.
H-bond
Specialized dipole-dipole attractions involved in intra/intermolecular attraction.
H bonded to very electronegative atoms. (O, N, F).
Octet rule
States that elements will be more stable with eight valence electrons.
