1. BELLRINGER Explain in complete sentences the difference between ionic compound, polar molecule and nonpolar molecules

2. Atoms, Molecules and Ions

3. 2

4. Period Group Alkali Metal Noble Gas Halogen Alkali Earth Metal

5. A molecule is an aggregate of two or more atoms in a definite arrangement held together by chemical bonds H2H2 H2OH2ONH 3 CH 4 A diatomic molecule contains only two atoms H 2, N 2, O 2, Br 2, HCl, CO A polyatomic molecule contains more than two atoms O 3, H 2 O, NH 3, CH 4

6. An ion is an atom, or group of atoms, that has a net positive or negative charge. cation – ion with a positive charge If a neutral atom loses one or more electrons it becomes a cation. anion – ion with a negative charge If a neutral atom gains one or more electrons it becomes an anion. Na 11 protons 11 electrons Na + 11 protons 10 electrons Cl 17 protons 17 electrons Cl - 17 protons 18 electrons

7. A monatomic ion contains only one atom A polyatomic ion contains more than one atom Na +, Cl -, Ca 2+, O 2-, Al 3+, N 3- OH -, CN -, NH 4 +, NO 3 -

8. 13 protons, 10 (13 – 3) electrons 34 protons, 36 (34 + 2) electrons Do You Understand Ions? How many protons and electrons are in Al 27 13 ? 3+3+ How many protons and electrons are in Se 78 34 2- ?

11. A molecular formula shows the exact number of atoms of each element in the smallest unit of a substance An empirical formula shows the simplest whole-number ratio of the atoms in a substance H2OH2O H2OH2O molecularempirical C 6 H 12 O 6 CH 2 O O3O3 O N2H4N2H4 NH 2

12. ionic compounds consist of a combination of cations and an anions the formula is always the same as the empirical formula the sum of the charges on the cation(s) and anion(s) in each formula unit must equal zero The ionic compound NaCl

13. Formula of Ionic Compounds Al 2 O 3 2 x +3 = +63 x -2 = -6 Al 3+ O 2- CaBr 2 1 x +2 = +22 x -1 = -2 Ca 2+ Br - Na 2 CO 3 1 x +2 = +21 x -2 = -2 Na + CO 3 2-

14. Some Polyatomic Ions (Table 2.3)

15. Chemical Nomenclature Ionic Compounds –often a metal + nonmetal –anion (nonmetal), add “ide” to element name BaCl 2 barium chloride K2OK2O potassium oxide Mg(OH) 2 magnesium hydroxide KNO 3 potassium nitrate

16. Transition metal ionic compounds –indicate charge on metal with Roman numerals FeCl 2 2 Cl - -2 so Fe is +2 iron(II) chloride FeCl 3 3 Cl - -3 so Fe is +3 iron(III) chloride Cr 2 S 3 3 S -2 -6 so Cr is +3 (6/2)chromium(III) sulfide

17. Molecular compounds –nonmetals or nonmetals + metalloids –common names H 2 O, NH 3, CH 4, C 60 –element further left in periodic table is 1 st –element closest to bottom of group is 1 st –if more than one compound can be formed from the same elements, use prefixes to indicate number of each kind of atom –last element ends in ide

18. HIhydrogen iodide NF 3 nitrogen trifluoride SO 2 sulfur dioxide N 2 Cl 4 dinitrogen tetrachloride NO 2 nitrogen dioxide N2ON2Odinitrogen monoxide Molecular Compounds TOXIC ! Laughing Gas

19. An acid can be defined as a substance that yields hydrogen ions (H + ) when dissolved in water. HCl Pure substance, hydrogen chloride Dissolved in water (H + Cl - ), hydrochloric acid An oxoacid is an acid that contains hydrogen, oxygen, and another element. HNO 3 nitric acid H 2 CO 3 carbonic acid H 2 SO 4 sulfuric acid

21. A base can be defined as a substance that yields hydroxide ions (OH - ) when dissolved in water. NaOH sodium hydroxide KOH potassium hydroxide Ba(OH) 2 barium hydroxide

22. ACTIVITY Discuss in a group and write a report about a molecule or compound given to you. Present your report to class. Distribution of work: person 1 – geometric structure of molecule or compound, 2 – properties of molecule or compound, 3 – properties if element 1, 4 - properties of elements 2 and 3. Distribution for groups: Group I – H2O, NaCl; II – CO, O3; III – KBr, NH3; IV – LiF, SO2; V – HCl, O2; VI – SO, F2; VII – SO2,Cl2 VIII – CO2, Br2

23. EXIT QUIZ 1. What is the purpose of geometric structure which we draw for a molecule or compound? 2. How can we show open ends for polar molecule using geometric structure? 3. How can we built compound or molecular structure using electric field of ionic compound or polar molecule?