Chem chap 2-3 Flashcards
How are covalent bonds formed?
They are bonds that are formed between two non-metals when they share their valence electrons.
How are ionic bonds formed?
They are bonds that are formed between a metal and non-metal when the metal gives away electrons to a non-metal.
What are the two types of compounds?
Ionic and Molecular Compounds.
What are the observable properties of ionic compounds?
Type of Bond - Ionic
Involves - Cation + Anion
Within the bond, electrons are transfering (M → NM).
Forces between compounds are strong.
Boiling/melting points are usually high.
Usual state at room temperature - Solid
Arrangement - Regular repeating array of cations and anions (“crystal lattice”)
Soluble? - Yes
Electrolyte? - Yes
Are there any prefixes for basic naming? - No
Chemical formula subscripts can be predicted by crossing charges.
What are the observable properties of molecular compounds?
Type of Bond - Covalent
Involves non-metals only.
Within the bond, electrons are shared.
Forces between compounds are weak.
Boiling/melting points are usually low.
Usual state at room temperature - Liquid/Gas
Arrangement - Individual molecules
Soluble? - usually no
Electrolyte? - usually no (except acids)
Are there any prefixes for basic naming? - Yes
Chemical formula cannot be predicted, it must be provided.
Draw the NaCl lewis diagram.
Please draw.
Draw the PCl5 lewis diagram.
Please draw.
Define electronegativity.
Electronegativity is a property that describes an atom’s ability to attract electrons.
Define non-polar covalent.
Bonded atoms that have no or little difference in electronegativity.
Define polar covalent.
Atoms that have significant differences (ΔEN > 0.5).
Is OCl2 a polar bond?
Yes
Is H2S a polar bond?
No
Is CH3Cl a polar bond?
Yes
Define polar molecule.
Polar molecules are entire molecules that have partially positive and negative ends.
What is the difference between a polar molecule and a polar bond.
A polar bond is one where the charge distribution between the two atoms in the bond is unequal. A polar molecule is one where the charge distribution around the molecule is not symmetric.
Is BeCl2 a polar bond or a polar molecule?
Polar bond.
Is H2S a polar bond or a polar molecule?
Neither.
Define intermolecular force (IMF).
Forces of attraction between molecules.
What is dipole-dipole force?
Attraction between polar molecules.
What are hydrogen “bonds” (H-bonds)?
Occurs in molecules where H is bonded to highly electrongative atoms.
nitrogen (N)
oxygen (O)
fluorine (F)
What is London dispersion force?
Weak attractive force experienced by ALL molecules.
Which IMFs does H2S have?
London Dispersion Force
Which IMFs does SO2 have?
London Dispersion Force, Dipole-Dipole Force
Which IMFs does CH3OH have?
London Dispersion Force, Dipole-Dipole Force, H-bond
The more _____ the Dipole-Dipole Forces in the molecule, the ________ the forces that exist between them.
polar, stronger
H-bonds are ________ than a regular dipole-dipole.
stronger
The ______ the LDF molecule, the more _________ it has.
larger, electrons
IMPORTANT THINGY TO MEMORIZE.
more electrons = larger number of LDF 🡪 stronger forces
more electrons = larger electron cloud 🡪 more polarizable 🡪 stronger forces
