8.2%20Ionic%20Bonding - PowerPoint PPT Presentation

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8.2%20Ionic%20Bonding

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8.2 Ionic Bonding Ionic Bonds Ionic bonds are made between metal and non-metal atoms Electrons are transferred from the metal atom to the non-metal atom Metal atoms ... – PowerPoint PPT presentation

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Title: 8.2%20Ionic%20Bonding


1
8.2 Ionic Bonding
2
Ionic Bonds
  • Ionic bonds are made between metal and non-metal
    atoms
  • Electrons are transferred from the metal atom to
    the non-metal atom
  • Metal atoms lose electrons form positive ions
    called cations.
  • Non metal atoms gain electrons form negative ions
    called anions.

3
Metals
  • Metals atoms lose electrons to form positive ions
    (an atom that loses or gains electrons) called
    cations.
  • E.g., Beryllium (Be) Group 2
  • Neutral atom Positive ion
  • 4 Ps 4 Ps
  • 4- Es 2- Es
  • 0 2
  • Valence Electrons
  • The electrons in the outer shell of an atom,
    which determines its power to combine with other
    elements

4
Non-metals
  • Non-metal atoms gain electrons to form negative
    ions called anions.
  • E.g., Carbon (Ca) Group 14
  • Neutral atom Negative ion
  • 6 Ps 6 Ps
  • 6- Es 10- Es
  • 0 4-

5
An example of ionic bonding..
  • Let us consider the bonding in the substance
    sodium chloride.
  • Na Cl- NaCl-
  • In this reaction the sodium (Na) atom loses 1
    electron while the chlorine atom accepts the
    electron in the transfer process.

6
NaCl
  • Thus we can say that sodium chloride is an ionic
    compound

7
NaCl
  • Cl-
  • Chloride ion
  • This charged atom contains
  • 17 Protons
  • 18- Electrons
  • 1
  • Na
  • Sodium ion
  • This charged atom contains
  • 11 Protons
  • 10- Electrons
  • - 1

8
Sodium Chloride
  • Thus NaCl
  • Once these two ions (An atom that has become
    charged be gaining or losing one or more
    electrons) have been formed, they will attract
    each other because of their opposite charges

9
CaO
  • Ca2 O2- Ca2O2-
  • In this reaction the calcium (Ca) atom loses 2
    electrons while the oxygen (O) atom accepts the
    two electrons in the transfer process.

10
  • Thus we can say that calcium oxide is an ionic
    compound

11
Calcium Oxide
  • Ca2 Calcium ion O2- Oxide ion
  • 20 Protons 8 Protons
  • 18- Electrons 10- Electrons
  • 2 2-
  • Once these two ions have been formed, they will
    attract each other because of their opposite
    charges.
  • There is an electrostatic attractive force
    present (like charges repel and unlike charges
    attract) that creates the chemical bond in the
    NaCl and CaO,called an ionic bond.

12
Lets try one..
  • Magnesium and Fluorine
  • Metal Non-metal
  • 12 Protons 9 Protons
  • 10- Electrons 10- Electrons
  • 2 1-
  • Mg2 F1- Mg2F1-
  • Chemical name Magnesium fluoride
  • Chemical Formula MgF2

13
  • Group 1 elements form cations with one positive
    charge.
  • Group 2 elements form cations with two positive
    charges.
  • Group 3 elements form cations with three positive
    charges.
  • Group 17 elements form anions with one negative
    charge.
  • Group 16 elements form anions with two negative
    charges.
  • group 15 elements form anions with three negative
    charges.
  • Group number on the periodic table indicates the
    number of electrons the atom will lose or gain.

14
Figuring out Ionic Charge
  • For metals, its the same as thegroup number
    (the column number).
  • For non metals, the charge is equal to whatever
    number needs to be addedto the group number to
    get 8. Group 8, (the noble gases), dont form
    ions asthey do not need to gain any electrons to
    have a full outer shell

15
More to try..
  • Potassium and Sulfur
  • Aluminium and Chlorine
  • Aluminum and Oxygen
  • Calcium and Fluorine

16
Bonding in Ionic Compounds
  • According to the ionic electrostatic model,
    solids such as NaCl consist of positive and
    negative ions arranged in a crystal lattice.
  • Each ion is attracted to neighbouring ions of
    opposite charge, and is repelled by ions of like
    charge this combination of attractions and
    repulsions, acting in all directions, causes the
    ion to be tightly fixed in its own location in
    the crystal lattice.
  • Sodium metal reacts with chlorine gas in a
    violently exothermic reaction to produce NaCl
    (composed of Na and Cl- ions)
  • 2Na(s) Cl2(g) -gt 2NaCl(s)
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