Unit 2: Chemical Interactions Chapter 5: Atoms & Bonding

1. Unit 2: Chemical InteractionsChapter 5: Atoms & Bonding Big Idea: Atoms of different elements combine to form compounds by gaining, losing, or sharing electrons

2. 4 Sections • Atoms, Bonding, & the Periodic Table • Ionic Bonds • Covalent Bonds • Bonding in Metals Mrs. Lee - Ch 5

3. Sec 1: Atoms, Bonding, & the Periodic Table KEY CONCEPTS • The number of valence electrons in an atom of an element determines many properties of that element, including the ways in which the atom can bond with other atoms • The periodic table reveals the underlying atomic structure of atoms, including the arrangement of the electrons Mrs. Lee - Ch 5

4. Valence electron Electron dot diagram Chemical bond Sec 1: Key Terms Mrs. Lee - Ch 5

5. Sec 2: Scientific Inquiry KEY CONCEPTS • Ionic bonds form as a result of the attraction between positive & negative ions • When ionic compounds form, the charges on the ions balance out Mrs. Lee - Ch 5

6. Sec 2: Ionic Bonds (cont’d) • For an ionic compound, the name of the positive ion comes first, followed by the name of the negative ion • In general, ionic compounds are hard, brittle crystals that have high melting points & conduct electricity when dissolved in water Mrs. Lee - Ch 5

7. Ion Polyatomic ion Ionic bond Ionic compound Chemical formula Subscript Crystal Sec 2: Key Terms Mrs. Lee - Ch 5

8. Sec 3: Covalent Bonds KEY CONCEPTS • The force that holds atoms together in a covalent bond is the attraction of each atom’s nucleus for the shared pair of electrons • Molecular compounds have low melting & boiling points & do not conduct electric current • Unequal sharing of electrons causes bonded atoms to have slight electrical charges Mrs. Lee - Ch 5

9. Covalent bond Molecule Double bond Triple bond Molecular compound Polar bond Nonpolar bond Sec 3: Key Terms Mrs. Lee - Ch 5

10. Sec 4: Bonding in Metals KEY CONCEPTS • Alloys are generally stronger & less reactive than the pure metals from which they are made • Metal atoms combine in regular patterns in which the valence electrons are free to move from atom to atom Mrs. Lee - Ch 5

11. Sec 4: Bonding in Metals (cont’d) • The “sea of electrons” model of metallic bonding helps explain the malleability, ductility, luster, high electrical conductivity, & high thermal conductivity of metals Mrs. Lee - Ch 5

12. Alloy Metallic bond Sec 4: Key Terms Mrs. Lee - Ch 5