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Chapter 2

Chemical Bonds

Covalent Bonds

Ionic Bonds

Hydrogen Bonds

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Chemical Bonds

A force that joins atoms is called a chemical bond.

Atoms form bonds to become stable which means they want to have a full outer shell.

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Chemical Compound

A compound is a substance made of the joined atoms

of two or more different elements.

Examples: H2O, CO2 , C6H12O6 , NaCl

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Types of Bonds:

Covalent Bonds -

Example: Bonds in C6H12O6

Ionic Bonds -

Example: Bonds in NaCl

Hydrogen Bonds -

Example: Bonds b/w H2O

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Covalent Bonds:

Covalent bonds form when two or more atoms share electrons to form a molecule.

The more electrons in the covalent bond, the more strongly the 2 atoms are joined.

Types:– Single bond – share 2 electrons.– Double bond – share 4 electrons.– Triple bond – share 6 electrons.

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Molecules

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Ionic Bonds

Atoms on the left side of the periodic table tend to give up or lose electrons.

Atoms on the right side of the periodic table tend to accept or gain electrons.

When an atom loses or gains one or more electrons, the result is an ion.

– Negative ion = gained 1 or more electrons.

– Positive ion = lost 1 or more electrons.

The strong attraction between oppositely charged ions is called an ionic bond.

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Hydrogen Bonds (Water)

Shared electrons are attracted more strongly by the oxygen nucleus than by the hydrogen nuclei.

This creates a partial positive end and partial negative end.

This unequal distribution of electrical charge is called polarity

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Hydrogen Bonds

Water molecules are attracted to each other by hydrogen bonds.