What I Absolutely Have to Know about IMFs to Survive the AP* Chemistry Exam.
Bonding in Solids In molecular solids, the particles are held to each other by IMFs. -- mol. solids...
-
Upload
dorothy-wood -
Category
Documents
-
view
214 -
download
2
Transcript of Bonding in Solids In molecular solids, the particles are held to each other by IMFs. -- mol. solids...
Bonding in Solids
In molecular solids, the particlesare held to each other by IMFs.
-- mol. solids are soft, w/low MPs
805
111–95*
18243
benzene
CH3 OH
toluene phenol
BP (oC)MP (oC)
Why?nonpolar;
weak LDFs
*stronger LDFs than C6H6, but doesn’t pack as closely in
solid form
H-bonding (strongest IMF)
In covalent-network solids, particlesare held together in large networksby covalent bonds.
-- harder – and have higherMPs – than molecular solids model of covalent-
network solid
-- e.g., diamond, graphite
model of molecular solid
In a molecularsolid, the particles
are held to eachother by IMFs. IMFs
good conductoralong its layers.
NOTE: Graphite has layers of covalently-bonded C atoms w/delocalized, p e–s (similar to benzene). Therefore, graphite is a...
The layers are held to each other by… weak LDFs.
e–e–
e–e–e–
e–
e–e–e–
e–
e– e–
e–e– e– e–
e–
e–e–
e–e–
+
–
Ionic solids consist of ions heldtogether by ionic bonds.
-- MPs depend largely on magnitude of charges.
-- e.g., MP of KCl = ______; MP of CaO = ______
776oC2572oC
Ionic size is a lesser factor.
potassium chloride (KCl) calcium oxide (CaO)
Metallic solids consist entirely of metal atoms.
-- these have HCP, CCP/FCC, or BCC structures, w/each atom touching 8 or 12 others
-- bonding is due to delocalized valence e– that are free to move throughout solid
** responsible for metallic properties(good heat and elec. conductors,
ductile/malleable, etc.)
-- metallic bond strength increases w/# of v.e–
e.g. MP of Li = ______; MP of Fe = ______ 181oC 1538oC
C-only or Si-anything: covalent-network
nonmetals only (including C-anything): molecular
metals only: metallic
metal-nonmetal: ionic
Metallic Properties
-- heat and elec. conductivity…
v.e– are free to move throughout material.
-- Via the v.e–, atoms w/high thermal energy can pass it on to others w/less.
-- Since the v.e– are charged (i.e., negatively), a DV causes them to migrate as a group.
e– e– e– e–
e– e– e– e– e– e– e– e– e– e– e– e–
e– e– e– e– e– e– e– e–
A spool of copper wire. Cu is anexcellent conductor, second only
to Ag (and followed by Au and then Al).
Metallic Properties, cont.
-- ductility/malleability…
e– e– e– e–
e– e– e– e– e– e– e– e– e– e– e– e–
e– e– e– e– e– e– e– e–
e– e– e– e–
e– e– e– e– e– e– e–
e–
e–
e–e–
e–
e– e– e– e–
e–
e–
e–e–
e–e–
e–
e–
e–
e–
(Some are pushed closer together,some are stretched farther apart).
The mobile v.e– move to counteractthose stresses.
Because v.e– in ionic and covalentsolids aren’t mobile, thesesubstances are insulators andare generally brittle.
When a metal is bent, the nucleiand core e– are forced into anonuniform arrangement.