LM19-20 Flashcards
Polar definition
Electrons are shared unequally and favor one side over the other
Nonpolar
Electrons are shared equally, are placed equidistant from each point
H2O is polar due to _____
Lone electron pairs on the central atom that cause it to have a non-linear arrangement
Bond length of H2 molecule
74 picometers
Octet rule
atoms want a filled outer shell (s2, s2p6)
∆EN, what does it show
difference in electronegativities, tells polarity and type of bond
Polarity
Separation of electrical charge in a bond/molecule
Covalent bonds’ ∆EN value
∆EN < 1.5 (approximate)
Ionic bonds’ ∆EN value
∆EN > 1.5 (approximate)
As ∆EN gets higher, ionic character (tendency to transfer electrons) ____
increases
Non-polar bonds’ ∆EN values
∆EN = 0 (approximate value, can reach up to ∆EN = 0.4)
Polar bonds’ ∆EN values
∆EN ≠ 0
EN possible values
0-4
Hydrogen EN value
2.1
Second row EN values
1.0-4.0, increasing by 0.5
Dipole Moment
Vectors that have magnitude and direction that show the difference in EN values between two atoms
A dipole moment points to the atom with _______
greater EN value
Dipole moment 𝛿+
Less electronegative atom
Dipole moment 𝛿-
More electronegative atom
A symmetrical molecule is _______
non-polar
An asymmetrical molecule is _______
polar
For a molecule to be non-polar, dipole vectors should ________
cancel out
Coulombic attraction
Attraction between oppositely charged particles
What potential energy does a hydrogen bond have?
-7 x 10^-19 J
As bond distance gets shorter, potential energy ______
decreases
Why does potential energy increase when atoms get extremely close?
The positive charges of the nuclei begin to repel each other
What is the bond length of atoms in relation to potential energy?
The internuclear distance at which potential energy is the lowest is the bond length
Endothermic process
The breaking of a bond through adding energy
Exothermic process
The forming of a bond through releasing energy
Lewis-Dot for Ionic Bonds: the anion will…
Be placed within brackets with a full shell
Lewis-Dot for Ionic Bonds: the cation will…
Be placed outside of the brackets
Lattice energy
energy required to break the bond in an ionic compound (how strongly bound it is)
Charge density
The quantity of charge in a certain volume
Characteristics that increase charge density
Decreased size, increased magnitude of charges (doubly-charged, etc)
Charge density’s relationship with lattice energy is
directly proportional
Charge density increases attraction because of
the increased magnitude of charges more strongly drawing opposite charges
Ranking charge density prioritizes ___
magnitude of charge
As attraction increases, bond length
decreases
As attraction increases, bond energy
increases
Polarization Power
ability of cation to distort anion electron cloud
Polarization power increases if a cation has _____
more charge density
Polarizability
tendency of anion to be polarized
Polarizability increases if an anion’s size _____
increases; so electron cloud is more distorted
