Unit 3 Part5 -2.2.5-6 -->Bond Polarity and Molecular Polarity Flashcards
26APR25 (19 cards)
What happens when there is a difference in electronegativities of the bonded atoms?
An unequal sharing of electrons
What is electronegativity?
The ability of an atom to attract electrons in a covalent bond
How does a bond become unsymmetrical?
When the more electrongative atom exerts a greater pulling power on the shared electrons and gains possesion
What is an unsymmetrical bond called?
Polar
What does bond dipole mean?
That a bond has two partially separated opposite electric charges
What do lone pairs cause?
Higher electron density
- Uneven charge distribution on the overall molecule
What does ionic mean?
Complete transfer of electrons of oppositely charged metals
What does pure covalent mean?
Equal sharing of electrons in discrete molecules
What does Polar covalent mean?
Unequal sharing of electrons with partial transfer of electrons
Ex of pure covalents?
Cl2
Ex of Polar covalents?
HF, HCl, HBr, Hl
What does molecular Polarity depend on?
Bond Polarity and Molecular geometry
What does bond Polarity depend on?
The charge separation between its two bonded atoms
- A result of differences in electronegativites
How can a molecule be IR active?
If it has an overall dipole moment related to the position and vibration of its bond
How can molecules become excited?
By absorbing electromagnetic IR
What does becoming excited mean?
To vibrate at higher frequencies
What is the one mode of vibration for diatomic molecules?
Stretching
What are the modes of vibration for polyatomic ions?
The stretching and bending of bonds
What is an IR active molecule that doesn’t have polar bonds?
CH4
