8th grade-ch. 1 sec. 4 covalent bonds

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Ch. 1 Sec. 4 s s

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Page 1: 8th Grade-Ch. 1 Sec. 4 Covalent Bonds

Ch. 1 Sec. 4

ss

Page 2: 8th Grade-Ch. 1 Sec. 4 Covalent Bonds
Page 3: 8th Grade-Ch. 1 Sec. 4 Covalent Bonds

covalent bonds

• usually form between 2 nonmetals

C2H6

Page 4: 8th Grade-Ch. 1 Sec. 4 Covalent Bonds

molecule •neutral group of atoms joined by covalent bonds

Page 5: 8th Grade-Ch. 1 Sec. 4 Covalent Bonds

CH4

Carbon has 4 electrons in its outer shell. It needs 4 more electrons.

Hydrogen needs 1.

Page 6: 8th Grade-Ch. 1 Sec. 4 Covalent Bonds
Page 7: 8th Grade-Ch. 1 Sec. 4 Covalent Bonds

Nonpolar bond• covalent bond in which valence

electrons are shared equally

• ex: oil

Page 8: 8th Grade-Ch. 1 Sec. 4 Covalent Bonds

Polar bond

Covalent bond in which electrons are shared unequally

Water molecules are polar

Page 9: 8th Grade-Ch. 1 Sec. 4 Covalent Bonds

Polar bond

Page 10: 8th Grade-Ch. 1 Sec. 4 Covalent Bonds

Polar bond

Page 11: 8th Grade-Ch. 1 Sec. 4 Covalent Bonds

Unequal sharing of electrons

Polar bond

Page 12: 8th Grade-Ch. 1 Sec. 4 Covalent Bonds

• Unequal sharing of an electron in a polar-covalent bond between 2 atoms is like 2 neighbors buying and sharing one snowblower.

• But one neighbor has a much

longer driveway than the other. • After a snowstorm, the snowblower will

spend much more of its time at the house with the longer driveway than the other.

• F, O, Cl have long driveways.

Be Nice, Clear Your IceBe Nice, Clear Your Ice

Page 13: 8th Grade-Ch. 1 Sec. 4 Covalent Bonds

Fluorine forms a nonpolar bond with

another fluorine atom.

In hydrogen fluoride, fluorine attracts

electrons more strongly than hydrogen does, so the bond formed is

polar.

Page 14: 8th Grade-Ch. 1 Sec. 4 Covalent Bonds

DOUBLE BOND

• 2 pairs of electrons are shared

Page 15: 8th Grade-Ch. 1 Sec. 4 Covalent Bonds

TRIPLE BOND

• 3 pairs of electrons are shared

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Page 18: 8th Grade-Ch. 1 Sec. 4 Covalent Bonds

molecular compound

• molecules having covalently bonded atoms

H2O

Page 19: 8th Grade-Ch. 1 Sec. 4 Covalent Bonds

Properties of molecular compounds

CH3CH2OH

Page 21: 8th Grade-Ch. 1 Sec. 4 Covalent Bonds

2. Poor conductors of electricity

Page 22: 8th Grade-Ch. 1 Sec. 4 Covalent Bonds

Click here for Ionic and Covalent Bonding Quiz

Page 23: 8th Grade-Ch. 1 Sec. 4 Covalent Bonds

YouTube video-Ionic and Covalent Bonding

Page 24: 8th Grade-Ch. 1 Sec. 4 Covalent Bonds

Review Time

Page 25: 8th Grade-Ch. 1 Sec. 4 Covalent Bonds

What holds covalently bonded atoms together?

• The force that holds atoms together in a covalent bond is the attraction of each atom’s nucleus for the shared pair of electrons.

Page 26: 8th Grade-Ch. 1 Sec. 4 Covalent Bonds

How does unequal sharing of electrons occur, and how does it affect molecules?

• Atoms of some elements pull more strongly on shared electrons than do atoms of other elements. As a result, the electrons are pulled more toward one atom, causing the bonded atoms to have slight electrical charges.

Page 27: 8th Grade-Ch. 1 Sec. 4 Covalent Bonds

What are the properties of molecular compounds?

• Molecular compounds generally have lower melting points and boiling points, and they do not conduct electricity when dissolved in water.