Polarity

Question 1

What is Polarity? What does it refer to?

Answer 1

• Polarity is the unequal sharing of electrons between bonded atoms
• Polarity refers to opposite poles (positive and negative charges)

Question 2

What type of bond is polarity associated with? Why?

Answer 2

Polarity is associated with covalent bonding

• Covalent bond: (mostly equal) Sharing of electrons
• There can be unequal electron sharing

(think of covalent bonds with ionic characteristics)

Question 3

What partial charges do the atoms in polar bonds recieve? Why

Answer 3

In polar bonds, electrons prefer the atom with greatest electronegativity

• Atom with higher EN: Partial negative
• Atom with lower EN: Partial positive

(the atom which attracts more electrons is partial negative)

Question 4

What determines if a molecule is polar?

Answer 4

Polar IF:

• Combination of positive and negative terminal atom charges (in comparison to central atom)
• There is/are lone pair(s) of electrons on central atom

(Only one of the criteria must be met for a molecule to be polar)

Question 5

What determines if a molecule is not polar?

Answer 5

Nonpolar IF:

• There are only negatives or only positive terminal atom charges (in comparison to central atom)

(Halogens are partial negative, and Hydrogen is positive)

Question 6

What is the “Like Dissolves Like” rule?

Answer 6

Rule stating that compounds will only dissolve in other compounds with similar characteristics

• Polar dissolves in polar
• Nonpolar dissolves in nonpolar
• Ionic dissolves in polar
• Covalent dissolves in nonpolar