1. Ch. 3 – Compounds

2. 3.1 Compounds are pure substances
made of more than one kind of atom joined together
are held together with chemical bonds.
two basic types: covalent and ionic.
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3. Covalent compounds
share electrons to form molecules
Example: water

4. Ionic compounds atoms gain or lose electrons to form ions
Example: NaCl

5. The positive ions attract all of the negative ions, and vice versa.
In ionic solids, the ions are packed together into a repeating pattern called a crystal lattice.
The positive ions attract all of the negative ions, and vice versa.
Example: Table salt (NaCl) has a one-to-one ratio of ions which creates a simple square-shaped ionic crystal:
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6. Polyatomic Ions (PAIs)
Covalent & ionic bonds can occur together
A polyatomic ion is created when a covalently bonded molecule gains or loses electrons becoming charged
Example: Hydroxide ion (OH-)
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7. There are many types of PAIs, but they occur in a few basic shapes.
Take the Section 3.1 Quiz