I

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Im Bond, Chemical Bond
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Atom the smallest unit of matter
indivisible
Helium atom
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electron shells

• Atomic number number of Electrons
• Electrons vary in the amount of energy they
  possess, and they occur at certain energy levels
  or electron shells.

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Electrons are placed in shells according to rules

• The 1st shell can hold up to two electrons, and
  each shell thereafter can hold up to 8 electrons.
  

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Octet Rule atoms tend to gain, lose or share
electrons so as to have 8 electrons

• C would like to
• N would like to
• O would like to

Gain 4 electrons
Gain 3 electrons
Gain 2 electrons
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Why are electrons important?

• Elements have different electron configurations
• different electron configurations mean different
  ways of bonding and different products from
  their reactions

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Noble gases
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Electron Dot Structures

• Symbols of atoms with dots to represent the
  outermost shell electrons
• 1 2 3 4 5
  6 7 2/8
• H? He
• ? ? ?
  ? ? ? ? ? ?
  ? ?
• Li? Be? ? B ? ? C ? ? N ?
  ? O ? F ? Ne
• ?
  ? ? ? ? ?
  ? ?
• ? ? ?
  ? ? ? ? ? ?
  ? ?
• Na? Mg? ? Al? ? Si ? ?P?
  ?S? Cl ? Ar
• ?
  ? ? ? ? ?
  ? ?

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Chemical bonds an attempt to fill electron shells

1. Ionic bonds
2. Covalent bonds
3. Metallic bonds

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Learning Check

• ?
• A. X would be the electron dot formula for
• 1) Na 2) K 3) Al
• ? ?
• B. ? X ? would be the electron dot formula
• ?
• 1) B 2) N 3) P

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IONIC BONDbond formed between two ions by the
transfer of electrons
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Formation of Ions from Metals

• Ionic compounds result when metals react with
  nonmetals
• Metals lose electrons to match the number of
  outermost shell electrons of their nearest noble
  gas
• Positive ions form when the number of electrons
  are less than the number of protons
• Group 1 metals ?? ion 1
• Group 2 metals ?? ion 2
• Group 13 metals ?? ion 3

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Formation of Sodium Ion

• Sodium atom Sodium
  ion
• Na ? e? ??? Na
• 2-8-1 2-8 ( Ne)
• 11 p 11 p
• 11 e-
  10 e-
• 0
  1

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Formation of Magnesium Ion

• Magnesium atom Magnesium ion
• ?
• Mg ? 2e? ?? Mg2
• 2-8-2 2-8 (Ne)
• 12 p 12 p
• 12 e-
  10 e-
• 0
  2

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Some Typical Ions with Positive Charges (Cations)

• Group 1 Group 2 Group 13
• H Mg2 Al3
• Li Ca2
• Na
• K

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Learning Check

• A. Number of outermost shell electrons in
  aluminium
• 1) 1 e- 2) 2 e- 3) 3 e-
• B. Change in electrons for octet
• 1) lose 3e- 2) gain 3 e- 3)
  gain 5 e-
• C. Ionic charge of aluminium
• 1) 3- 2) 5- 3) 3

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Solution

• A. Number of outermost shell electrons in
  aluminium
• 3) 3 e-
• B. Change in electrons for octet
• 1) lose 3e-
• C. Ionic charge of aluminium
• 3) 3

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Learning Check

• Give the ionic charge for each of the following
• A. 12 p and 10 e-
• 1) 0 2) 2 3) 2-
• B. 50p and 46 e-
• 1) 2 2) 4 3) 4-
• C. 15 p and 18e-
• 2) 3 2) 3- 3) 5-

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Ions from Nonmetal Ions

• In ionic compounds, nonmetals gain electrons from
  metals
• Nonmetal add electrons to achieve the octet
  arrangement
• Nonmetal ionic charge
• 3-, 2-, or 1-

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Fluoride Ion

• unpaired electron octet
• ? ? ? ? 1 -
• F ? e? F
• ? ? ? ?
• 2-7 2-8 ( Ne)
• 9 p 9 p
• 9 e- 10 e-
• 0 1 -
• ionic charge

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Ionic Bond

• Between atoms of metals and nonmetals
• Bond formed by transfer of electrons
• Produce charged ions. Conductors and have high
  melting point.
• Examples NaCl, CaCl2, K2O

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1). Ionic bond electron from Na is transferred
to Cl, this causes a charge imbalance in each
atom. The Na becomes (Na) and the Cl becomes
(Cl-), charged particles or ions.
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http//www.youtube.com/watch?vFtw7a5ccubs
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COVALENT BONDbond formed by the sharing of
electrons
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Covalent Bond

• Between nonmetallic elements
• Formed by sharing electron pairs
• Stable non-charged particles, they are not
  conductors at any state
• Examples O2, CO2, C2H6, H2O, SiC

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Covalent Bonds
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• Bonds in all the polyatomic ions and diatomics
  are all covalent bonds

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when electrons are shared equally
COVALENT BONDin elements
H2 or Cl2
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2. Covalent bonds- Two atoms share one or more
pairs of outer-shell electrons.
Oxygen Atom
Oxygen Atom

Oxygen Molecule (O2)
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when electrons are shared but shared unequally
COVALENT BONDS in compounds
H2O
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- water is a polar molecule because oxygen is
more electronegative than hydrogen, and therefore
electrons are pulled closer to oxygen.
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METALLIC BONDbond found in metals holds metal
atoms together very strongly
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Metallic Bond

• Formed between atoms of metallic elements
• Electron cloud around atoms
• Good conductors at all states, lustrous, very
  high melting points
• Examples Na, Fe, Al, Au, Co

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Ionic Bond, A Sea of Electrons
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Metals Form Alloys
Metals do not combine with metals. They form
Alloys which is a solution of a metal in a
metal. Examples are steel, brass, bronze and
pewter.
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Compounds and Their Bonds

• Ionic Compounds
• Naming Ionic Formulas

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Ionic Compounds

• Attraction between ions and - ions
• Electrons go from metals to nonmetals
• electron transfer
• metal nonmetal ion ion
• Electrons lost Electrons gain

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Formulas of Ionic Compounds

• Formulas of ionic compounds are determined from
  the charges on the ions
• atoms ions
• ? ? ? ?
• Na ? ? F ?? Na F ??
  NaF
• ? ?
  ? ?
• sodium fluorine sodium fluoride
  formula
• Charge balance 1 1-
  0

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Writing a Formula

• Write the formula for the ionic compound that
  will form between Ba2 and Cl?.
• Solution
• 1. Balance charge with and ions
• 2. Write the positive ion of metal first, and
  the
• negative ion Ba2 Cl?
  Cl?
• 3. Write the number of ions needed as
• subscripts BaCl2

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Learning Check

• Write the correct formula for the compounds
  containing the following ions
• A. Na, S2-
• 1) NaS 2) Na2S 3) NaS2
• B. Al3, Cl-
• 1) AlCl3 2) AlCl 3) Al3Cl
• C. Mg2, N3-
• 1) MgN 2) Mg2N3 3) Mg3N2

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Solution

• A. Na, S2-
• 2) Na2S
• B. Al3, Cl-
• 1) AlCl3
• C. Mg2, N3-
• 3) Mg3N2

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Naming Binary Ionic Compounds

• Contain 2 different elements
• Name the metal first, then the nonmetal as -ide.
• Use name of a metal with a fixed charge
• Groups 1A, 2A, 3A
• and Ag, Zn, and Cd
• Examples
• NaCl sodium chloride
• ZnI2 zinc iodide
• Al2O3 aluminum oxide

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Learning Check

• Complete the names of the following binary
  compounds
• Na3N sodium ________________
• KBr potassium ________________
• Al2O3 aluminum ________________
• MgS _________________________

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Solution

• Complete the names of the following binary
  compounds
• Na3N sodium nitride
• KBr potassium bromide
• Al2O3 aluminum oxide
• MgS magnesium sulfide

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Learning Check

• A. The formula for the ionic compound of
• Na and O2- is
• 1) NaO 2) Na2O 3) NaO2
• B. The formula of a compound of aluminum and
  chlorine is
• 1) Al3Cl 2) AlCl2 3) AlCl3
• C. The formula of Fe3 and O2- is
• 1) Fe3O2 2) FeO3 3) Fe2O3

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Solution

• A. The formula for the ionic compound of
• Na and O2- is
• 2) Na2O
• B. The formula of a compound of aluminum and
  chlorine is
• 3) AlCl3
• C. The formula of Fe3 and O2- is
• 3) Fe2O3

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Learning Check

• Name the following compounds
• A. CaO
• 1) calcium oxide 2) calcium(I) oxide
• 3) calcium (II) oxide
• B. SnCl4
• 1) tin tetrachloride 2) tin(II) chloride
• 3) tin(IV) chloride
• C. Co2O3
• 1) cobalt oxide 2) cobalt (III) oxide
• 3) cobalt trioxide

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Solution

• Name the following compounds
• A. CaO 1) calcium oxide
• B. SnCl4 3) tin(IV) chloride
• C. Co2O3 2) cobalt (III) oxide

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Q1. Name a metal in group 1 that is in the same
period as Magnesium.
Q2. Name a metal in group 2 that in the same
period as Lithium.
Q3. Name a non-metal in the same group as
Nitrogen.
Q4. Name a noble gas in the same period as
Oxygen.
Q5. Name a gas in group 7 that is in the same
period as Aluminium.
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Objective 1. Learn the scientific method for
naming compounds. 2. There are three rules for
naming compounds the ide rule, the ate rule
and the same rule.
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Rule 1 When two elements combine the ending is
usually ide. metal goes first Sodium
Chloride Magnesium Oxide Iron Sulphide
Cl
Na
Mg
O
Fe
S
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Rule 2 When three or more different elements
combine and one of them is Oxygen, the ending
will be ate. metal goes first Copper
Sulphate Calcium Carbonate
O
O
Cu
S
O
O
O
O
C
Ca
O
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Rule 3 When two identical elements combine, the
name does not change. H2 Hydrogen F2
Fluorine N2 Nitrogen Cl2 Chlorine O2
Oxygen
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Name the following compound
Na2O
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Name the following compound
CuSO4
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Name the following compound
MgSO4
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Name the following compound
ZnO
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Name the following compound
MgCl2
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Name the following molecule
H2
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Name the following compound
KI
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Name the following compound
AgNO3