Chemical bonds hold atoms together in compounds and determine compounds' properties. Compounds have definite compositions and properties unlike their constituent elements. Ionic bonds form when atoms transfer electrons to become ions of opposite charge, binding in crystalline structures. Covalent bonds form when atoms share electron pairs, binding as individual molecules with properties depending on size and shape. Metallic bonds allow electron delocalization in metal crystals. Different bonding structures give compounds distinctive physical and chemical characteristics.

2. Section 2.1 Elements Combine to Form Compounds

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7. Section 2.2 Chemical Bonds Hold Compounds Together

10. Page 48 Sodium has one election in its outer ring, chlorine has 7. If Sodium give up 1 and chlorine accepts 1, the result is two completed outer rings. Everyone is happy 

15. Page 51 Nonpolar Compound Polar Compound

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19. Section 2.3 Substances’ Properties depend on Their Bonds.

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