1. Notes #5: Electronegativity
WCHS Chemistry

2. Covalent Bonds Ionic Bonds
IONIC & COVALENT BONDS
Covalent Bonds
e- are shared to reach 8
Ionic Bonds
Give or take e-
Opposites attract _ +
Equal Sharing
Unequal Sharing
**Sharing isn’t always equal!**
Electronegativity = the ability of an atom to attract e-
A.k.a. How much an atom can “pull”
on an e-

3. (How hard an atom can pull on e-) Atoms don’t pull as hard
Increases (pulls more)
Closer & closer to 8 v.e-
Atoms pull harder on e-
Atoms get bigger: e- far away
Decreases (less pull)
Atoms don’t pull as hard

4. F pulls so hard that it takes the e- from K
4.1
4.1
4.1
4.1
0.91
2.5
F pulls so hard that it takes the e- from K
Equal pulling, so equal sharing
F pulls harder, so e- stays closer to F

5. NONPOLAR Covalent Bond = NOT CHARGED b/c of EQUAL sharing of e-
4.1
4.1
NONPOLAR Covalent Bond
= NOT CHARGED b/c of EQUAL sharing of e-
POLAR Covalent Bond
= Slightly CHARGED b/c of UNEQUAL sharing of e-
Must write in slight charges or “poles” like on a battery! 𝛅- 𝛅+
2.5
4.1

6. BIG IDEAS Not all sharing is equal Unequal sharing = POLAR covalent
Equal sharing = NONPOLAR covalent
NO sharing = IONIC!

7. *Draw Lewis Dot structures 1st to see which elements are involved in a bond
EXAMPLES
0.3 difference
2.2
2.5

8. Look at chart on bottom of page...

9. *Draw Lewis Dot structures 1st to see which elements are involved in a bond
EXAMPLES
0.3 difference
NONPOLAR
Covalent
(Equal Sharing)
3.07
2.2
2.2 𝛅-
2.5 𝛅+
0.87 difference
POLAR Covalent
(Unequal Sharing)

10. EXAMPLES IONIC NO sharing _ +
*Draw Lewis Dot structures 1st to see which elements are involved in a bond
EXAMPLES
IONIC
NO sharing
1.01
2.83 _ +
1.82 difference

11. No Poles
→ Equal sharing
POLES (slight charges)
→ Unequal sharing
NO SHARING!
→ Full charges (take or give e-)

12. Steps for Classifying Bonds: Draw all Lewis Dot Structures
IMPORTANT: In the future → Check ALL BONDS!
There can be MULTIPLE types of bonds in one molecule!
Steps for Classifying Bonds:
Draw all Lewis Dot Structures
Assign EN numbers and check differences between all UNIQUE bonds
Use chart to determine nonpolar, polar, or ionic
Assign slight charges if polar or full charges if ionic