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This comprehensive overview explores the three main types of chemical bonds: metallic, ionic, and covalent. It highlights the importance of chemical bonds in forming stable compounds from uncombined atoms and the unique properties that emerge from these compounds. Key concepts such as valence electrons, oxidation numbers, and the behavior of elements when forming bonds are discussed. The guide includes examples of bond formation, including NaCl (ionic) and H2O (covalent), and encourages readers to practice with Bohr models or Lewis dot diagrams to solidify their understanding.
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Chemical Bonds Metallic Ionic Covalent
Background Information • Most atoms are not found uncombined in nature. • Atoms combine to become stable (“stable 8”). • Chemical bonds are the forces that hold atoms/ions together. • The properties of elements are different from the properties of their compounds.
Periodic Patterns • Column number=number of valence (outer electrons) • Atoms lose, gain, or share electrons to have a stable octet (8 valence electrons) • Oxidation numbers are + or – numbers that indicate whether an atom loses/gains electrons to become stable He N Ne B C O F Li Be Gains 2 Gains 1 Gains 3 Loses 2 Loses 3 Loses 1 -1 -2 -3 +3 +2 +1
Types of Bonds Covalent Nonmetal+Nonmetal Electrons are Shared Form network of molecules Do not conduct when dissolved in water Low melting & boiling points Ionic Metal+Nonmetal Electrons are Transferred Form Crystals Conduct when dissolved in water High melting & boiling points Metallic Metal+Metal Equal Sharing of Electrons Conduct electricity & heat Easily shaped
Bonding & Valence Electrons • Elements try to have 8 valence electrons (except H, He, Li, Be, B) • Elements will lose, gain, or share electrons • If elements have less than 4 electrons, they will lose electrons; these acquire a positive charge • If elements have more than 4 electrons, they will gain electrons; these acquire a negative charge
Now You Try:Use Bohr Models or Lewis Dot Diagrams to Show Bonding for 1) Ionic Bonding Between Mg & O 2) Covalent Bonding for CO2