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Chapter 6 Section 2 : Ionic and Covalent Bonding. Chemical Bonds. Atoms form bonds so that each atom has a stable electron configuration Two types of chemical bonding Ionic Covalent. Ionic Bonds. Form from attractions between oppositely charged ions Ionic Bonds:
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Chemical Bonds • Atoms form bonds so that each atom has a stable electron configuration • Two types of chemical bonding • Ionic • Covalent
Ionic Bonds • Form from attractions between oppositely charged ions • Ionic Bonds: • The attractive force between oppositely charged ions, which form when electrons are transferred from one atom to another • TRANSFER of ELECTRONS
Ionic Bonds • A positive ion (cation) transfers an electron to a negative ion (anion) • Forms a network, not molecule • HIGH melting point, usually form crystals • Conduct electricity when dissolved in water • Formula unit • The smallest ratio of ions in an ionic compound
Covalent Bonds • Atoms joined by covalent bonds share electrons • Covalent Bond • A bond formed when atoms share one or more pairs of electron • form between nonmetals • Can be solids, liquids, or gases
Covalent Bonds • Atoms may share more than one pair of electrons • Forms a double bond if two pairs are shared • Forms a triple bond if three pairs are shared • The more bonds, the stronger the attraction
Covalent Bonding • Electrons are not always shared equally • Nonpolar – electrons ARE shared equally • Polar – electrons ARE NOT shared equally • Water H2O
Metallic Bonding • A bond formed by the attraction between positively charged metal ions and the electrons around them • Ex) Copper, Gold • Flexible • Conduct electricity • Atoms and electrons move freely throughout the metal
Polyatomic Ions • An ion made of two or more atoms • Acts a single unit in a compound • Grouped by parentheses • Ex) (NH4)2SO4
Polyatomic Ions • Names of anions relate to their oxygen content • “-ate” used to name ions with more oxygen atoms • Ex) sulfate (SO42-) • “-ite” used to name ions with fewer oxygen atoms • Ex) sulfite (SO32-)
Quiz • 1. In which type of bond are electrons shared between atoms? A. Ionic B. Covalent C. Metallic
2. Which type of bond creates a crystalline structure? A. Ionic B. Covalent C. Metallic
3. Which type of bond usually forms between two nonmetals? A. Ionic B. Covalent C. Metallic
4. Which type of bond forms a structure which is often described as an "electron sea"? A. Ionic B. Covalent C. Metallic
5. Which bond is characterized by the formation of oppositely charged particles? A. Ionic B. Covalent C. Metallic
6. In which type of bond are one or more electrons transferred from one atom to another? A. Ionic B. Covalent C. Metallic
7. Which of the following is NOT a characteristic of ionic substances? A. Conduct electricity in solution form. B. Have high melting points. C. Usually dissolve in water. D. Are usually gases at room temperature.
8. Which of the following is NOT a characteristic of metallic substances? A. Are lustrous, malleable, and ductile. B. Conduct electricity. C. Have low melting points. D. Are usually solids at room temperature.
9. Which of the following is NOT a characteristic of covalent substances? A. Have low melting points. B. Sometimes dissolve in water. C. Usually form small, individual molecules. D. Conduct electricity.
10. Why do atoms form chemical bonds? A. To increase their potential energy. B. To become more stable. C. To gain more valence electrons. D. To obtain a higher electronegativity.
Choose one of the following to show the difference and similarities in covalent, ionic, and metallic bonding. • Story • Poem • Comic strip • Play