Unit 2 part 4 - Electronegativity Flashcards
23MAR25 Pg. 193-5 and 302-3
What are polar bonds a result of?
Unequal sharing of electrons
When does an unequal sharing of electrons occur?
When there is a difference in the electronegativities of the bonded atoms
What is electronegativity?
the ability of an atom to attract electrons in a covalent bonds
How are electronegativities described?
Using Pauling scale from 0-4
How does the more electronegative atom gains gain more ‘ possession’ of the electron pair and what does this cause?
b/c it has a greater pulling power on the shared electrons. This causes the bond to be unsymmetrical and becomes polar
What are dipoles?
Partial charges assigned to a molecule according to it’s electronegativity
What type of bond is it when electronegativity is less than 0.5?
Non-polar covalent
What type of bond is it when electronegativity is between 0.5 and 1.8?
Polar covalent
What type of bond is it when electronegativity Is more than 1.8?
Ionic
Why does electronegativity not apply to group 18?
B/c they don’t form covalent bonds
Reasons for the bonding depending on the electronegativity?
- Atomic radii increases down a group
- Atomic radii decreases across a row
What does it mean for electronegativity if atomic radii increases down a group?
- Bonding electrons are in higher energy levels resulting in distance from the nucleus
- experience more shielding from inner electrons
Meaning, atoms with larger radii don’t attract bonding electrons
What does it mean for electronegativity if atomic radii decreases across a row?
- Atoms in the same row are at same energy levels (same distance from nucleus)
- Shielding stays the same
- Zeff increases
Meaning, atoms w/smaller radii will have stronger attraction to bonding electrons
