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Types of CHEMICAL

BONDS

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Essential Question: How does the numberand arrangement of electrons affect theway that atoms bond?

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• A chemical bond is a strong attractive force between atoms to form a molecule or compound.

• Formed by either:– transferring valence e- (losing or gaining)OR– sharing valence e-

Chemical Bond

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• Valence electrons are distributed as shared or BOND PAIRS and unshared or LONE PAIRS.

•••

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H Cllone pair (LP)shared or

bond pair

This is called a LEWIS DOT structure.

Valence Electrons

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• Octet Rule–most atoms form bonds in order to have 8 valence e-

OR –a full outer energy levellike the Noble Gases!

Ne

¨ Stability is the driving force behind bond formation!

Octet Rule

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1. Ionic bonds2. Covalent bonds

-Polar Covalent3. Metallic bonds

Types of Chemical Bonds

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• An atom that gains or loses electrons is called an ion.–Atoms that gain electrons have a NEGATIVE charge called an ANION.

–Atoms that lose electrons have a POSITIVE charge called a CATION.

Ions

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Ionic BondsFormed by attraction of two ions with opposite charge (+) and (-).

Electrons are transferred from:

• Metal cation (+) to • Nonmetal anion (-)Ionic compounds are called salts and form a crystal lattice.

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An 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.

10Ionic Bonds form between

ions.

11Ionic Bonds: One Big Greedy Thief Dog!

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Crystal Lattice• The ions that make up an ionic

compound are bonded in a repeating 3D pattern called a crystal lattice.

13Covalent BondsFormed by sharing of electron pairs between 2 nonmetals.

More than one pair of electrons can be shared (double bonds, triple bonds)

14Ionic Bond = Metal + NonmetalCovalent Bond = Nonmetal +

NonmetalMetallic Bond = Metal + Metal