Docsity
Docsity

Prepare for your exams
Prepare for your exams

Study with the several resources on Docsity


Earn points to download
Earn points to download

Earn points by helping other students or get them with a premium plan


Guidelines and tips
Guidelines and tips

Electronegativity and Bond Character: Understanding Polarity and Intermolecular Forces, Exams of Chemistry

An overview of electronegativity, its relationship with electron affinity and bond character, and how it impacts the formation of polar and nonpolar covalent bonds. The document also discusses intramolecular and intermolecular forces, including dispersion forces, dipole-dipole interactions, and hydrogen bonds, and their relative strengths.

Typology: Exams

2021/2022

Uploaded on 09/12/2022

myboy
myboy 🇺🇸

4.4

(72)

260 documents

1 / 13

Toggle sidebar

This page cannot be seen from the preview

Don't miss anything!

bg1
POLARITY & FORCES
pf3
pf4
pf5
pf8
pf9
pfa
pfd

Partial preview of the text

Download Electronegativity and Bond Character: Understanding Polarity and Intermolecular Forces and more Exams Chemistry in PDF only on Docsity!

POLARITY & FORCES

ELECTRONEGATIVITY

 Electron Affinity – a measure of the tendency of an atom to accept an electron

 Increases across a period  Decreases down a group  This is why your halogens create anions – they have high electron affinities!

 Electronegativity – measure of the tendency of an atom to attract electrons

when in a compound and sharing electrons

 Increases across a period  Decreases down a group  Most electronegative = F

BOND CHARACTER

Electronegativity Difference Bond Character

1.7 Mostly Ionic 0.4 – 1.7 Polar Covalent < 0.4 Mostly Covalent 0 Nonpolar Covalent

NONPOLAR COVALENT BOND

 Nonpolar covalent bond - nuclei of atoms pull on electrons equally; bonding electrons are shared

equally.

 H 2 , N 2 , O 2 , Cl 2

 No difference in the electronegativity

between the atoms.

POLAR COVALENT BONDS

POLARITY OF MOLECULES

 Polarity of a molecule depends on the individual bonds and the shape of the overall molecule.  If the polar bonds are symmetrical, the polarity cancels out and the overall molecule is nonpolar.  If the polar bonds are asymmetric, the polarity persists in the molecule.

INTERMOLECULAR FORCES

 Intermolecular - attractive forces between molecules

 Inter – between

 All intermolecular forces are weaker than intramolecular forces

 Dispersion

 Dipole-dipole

 Hydrogen bonds

INTERMOLECULAR FORCES

 Dispersion Forces – weak forces that result from temporary shifts in the density of electrons in electron clouds  Larger molecules experience larger dispersion forces  Dipole-dipole – attractions between oppositely charged regions of polar molecules  Hydrogen Bonds – dipole-dipole attraction between molecules with a H bonded to a small, electronegative atom that has one lone electron pair  H bonded to a F, O, or N  From weakest to strongest: Dispersion  Dipole-dipole  Hydrogen Bonds

INTER & INTRA MOLECULAR FORCES & PROPERTIES

 Stronger the force, the more energy is needed to break the bond  Energy needed to break a metallic or an ionic bond will be much higher than the energy needed to break a covalent bond  Separating NaCl will require more energy than separating CO 2  Energy needed to overcome intermolecular forces will increase with an increase in force strength  Boiling H 2 O will require more energy than boiling H 2 S because H 2 O experiences hydrogen bonding and H 2 S experiences only a slight dipole-dipole