First Exam Flashcards
(20 cards)
How are sigma bonds formed ?
By 2 s orbitals overlapping or by end on end overlap of two p orbitals.
How are pi bonds formed?
By sideways overlap of two parallel p orbitals
What is the bond length relationship with halogens and hydrogens?
As the halogen increases in size, so does the bond length
What happens to the strength of a bond as the length of the bond increases ?
The bond strength decreases
What are delocalized electrons?
Electrons without a particular place, movement exists!
What kind of electrons are
Delocalized ?
Pi electrons
Why are resonance hybrids more accurate than resonance contributors ?
Contributors do not show actual electron distribution because electrons are always moving !
Why are amides so strong ?
Because of their resonance ! Building block of hair and skin !
Name 4 qualities that lower the stability of resonance.
- Atom has incomplete octet
- negative charge isn’t on most electronegative atom
- Charges exist !
- A positive charge that is not on the most elect positive atom
Define acid
Donor of protons !!
Define base
Accepts protons
What does a low pka mean?
The acid is strong and therefore more likely to give up a proton
Are stable bases weak or strong?
Weak!
Start with strong acid means….
End with a weak base
Start with a weak acid…
End with a strong/unstable base
Describe the relationship between electro negativity, acid strength, and base strength
Electro negativity increases
Acid strength increases
Base strength decreases/ base stability increases !
When determining acid strength, which trend overrides electro negativity?
SIZE
Where is the proton on a strong acid ?
On the most electronegative atom (like oxygen)
How do substituents affect the strength of an atom?
As the element moves away from the proton, it becomes less acidic
How do resonance and stability relate?
Low resonance = high stability
