Selfquiz

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Self-quiz

• Compound Name Dc Bonding Structure
• ionic, (non)polar covalent (molecular/perio
  dic)
• SO3
• SrCl2
• Mn2O3
• PCl3
• PO4
• ammonium sulfate
• silicon dioxide

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Todays goals

• Molecular compounds
• Valence/core review
• Lewis dot notation

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Admin stuff

• OWLs OWLs for Mon. will be added shortly
• Reading Current Ch. 9
• Test 3 Mon, Nov. 20th, 6-730 PM

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Naming compounds
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Chemical bonding
Covalent
Ionic
AB-
AB
(shared electrons)
(transferred electrons)
Different naming rules for each
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Molecular compounds (neutral)

• Focus on binary non-metal compounds ( hydrogen)
• Molecular indicates a specific atomic
  arrangement
• Molecular compounds do not exist as extended
  solids
• No ionic subcomponents cannot be subdivided!
  (except H)
• Examples
• HF hydrogen fluoride CO carbon monoxide
• H2S dihydrogen sulfide PCl3 phosphorus trichloride

(Partial) positive and negative chemical species
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Naming molecular compounds

• Normally positive component before negative
  component
• Usually write in order of increasing group (18
  groups)
• Write full element name of 1st, anionic name of
  2nd
• Include number of each atom using standard
  prefixes
• Exceptions If first prefix is mono-, omit it
• Some common names supersede rules
• Prefixes include
• CO carbon monoxide
• CO2 carbon dioxide
• NF3 nitrogen trifluoride
• CBr4 carbon tetrabromide
• PCl5 phosphorus pentachloride

• hexa-
• hepta-
• octa-
• nona-
• deca-

Number prefixes are NOT used for ionic compounds
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Molecular compounds (neutral)

• Some common names
• H2O water CH4 methane
• NH3 ammonia C2H6 ethane
• N2H4 hydrazine C3H8 propane
• PH3 phosphine
• NO nitric oxide
• N2O nitrous oxide

Organic compounds often ignore group order
connectivity
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Names of some molecular compounds

• silicon tetrabromide
• bromine trifluoride
• diboron trioxide
• nitrous oxide

• SiBr4
• BrF3
• B2O3
• N2O

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Names of some molecular compounds

• Give formulas and name the compounds with
• two nitrogens and five oxygens
• three sulfurs and four phosphoruses
• one oxygen and two fluorines
• ten fluorines and two sulfurs
• six hydrogens and two carbons

• N2O5
• P4S3
• OF2
• S2F10
• C2H6

• dinitrogen pentaoxide
• tetraphosphorus trisulfide
• oxygen difluoride
• disulfur decafluoride
• ethane

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Valence electrons
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Valence electrons

• Atoms which can be shared or removed are called
  valence electrons
• Chemically inert electrons are known as the core
  electrons.
• How can we tell which are which?

NO3 CO3 2 SO4 2 PO43 ClO4 CrO42
MnO4
Main group (1A-8A) valence electrons group
(-gtouter s,p) Transition metals valence
electrons outer s and d electrons
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Valence electrons

• Main group elements (1A-8A)
• Li Be B C N O F Ne
• Valence electrons

How many valence electrons does Ne have? (A)
0 (B) 2 (C) 8 (D) 10 (E) 18
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Valence electrons

• How many valence electrons does Br have?
• -1
• 1
• 7
• 8
• 17
• 18
• 35

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Valence electrons

• How many total valence electrons are in the ion
  CO32-
• 2
• 4
• 6
• 18
• 22
• 24
• 36

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Lewis dot structures

• A
• A
• A

A A A
Each dot 1 electron
Each line 2 electrons
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Lewis dot picture of bonds

• Ionic bonding
• Covalent bonding

• Ionic bonding often gives configuration of noble
  gas
• Covalent bonding does too if you count shared e-

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Octet rule

• The tendency of molecules and polyatomic ions to
  have structures in which there are eight
  electrons in the outermost shell of each atom is
  known as the octet rule
• The origin of this is the enhanced stability of
  full shells of electrons. This allows us to
  understand covalent bonds.
• An octet is 8 e- for most non-metals.

• An octet is 2 e- for hydrogen.

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Lewis dot structures

• A
• A
• A

A A A
How many electrons are on each of these atoms?
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Connectivity

• Main group elements (1A-8A)
• Lewis dot structures
• Li Be B C N O F Ne

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Overhead slides
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Table of electronegativities