1. Chapter 2 Atoms, Molecules and Ions Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

2. Chapter 2 (p.49-68) Atomic number, mass number and isotopes. The periodic table. Molecules and ions. Chemical formulas. Naming compounds. Tables 2.1- 2.2 – 2.3 – 2.4 - 2.5 – 2.6 – 2.7 Examples 2.1- 2.2 – 2.3 – 2.4 – 2.5 – 2.6 – 2.7 – 2.8 – 2.9

3. mass p = mass n = 1840 x mass e - 2.2

4. X A Z Mass Number Atomic Number Element Symbol 2.3 Atomic number, Mass number and Isotopes Mass number (A) = number of protons + number of neutrons = atomic number (Z) + number of neutrons Atomic number (Z) = number of protons in nucleus

5. 2.3 Isotopes hydrogen deuterium tritrium Isotopes are atoms of the same element (X) with different numbers of neutrons (mass number) U 235 92 U 238 92 Examples of Isotopes

6. 6 protons, 8 (14 - 6) neutrons, 6 electrons Do You Understand Isotopes? 2.3 How many protons, neutrons, and electrons are in C 14 6 ? How many protons, neutrons, and electrons are in C 11 6 ? Define the element X 63 29 ? 6 protons, 5 (11 - 6) neutrons, 6 electrons The element with atomic number 29 is cupper (Cu) and its mass number is 63

8. Period Group Alkali Metal Noble Gas Halogen Alkali Earth Metal 2.4 Periodic Table is a chart in which elements having similar chemical and physical properties are grouped together in this table the elements are arranged by atomic number

9. Allotrope is one of two or more distinct forms of an element as O 2, O 3. Allotropes * Oxygen O-O (O 2 ) and Ozone O 3 * Diamond and Graphite Examples of Allotropes

10. Example for Allotropes Diamond and Graphite

11. Graphite Diamond

12. Chemistry In Action Natural abundance of elements in Earth’s crust Natural abundance of elements in human body 2.4

13. H2H2 H2OH2ONH 3 CH 4 A diatomic molecule contains only two atoms H 2, N 2, O 2, Br 2, HCl, CO, NO, KCl A polyatomic molecule contains more than two atoms O 3, H 2 O, NH 3, CH 4, NaOH 2.5 The monatomic molecules are the single atoms of noble gases; He, Ne, Ar, Kr, Xe, Rn. A molecule is an aggregate of two or more atoms in a definite arrangement held together by chemical forces.

14. 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 2.5

15. A monatomic ion contains only one atom A polyatomic ion contains more than one atom 2.5 Na +, Cl -, Ca 2+, O 2-, Al 3+, N 3- OH -, CN -, NH 4 +, CO 3 2-, NO 3 -

16. 13 protons, 10 (13 – 3) electrons 34 protons, 36 (34 + 2) electrons Do You Understand Ions? 2.5 How many protons and electrons are in ?Al 27 13 3+ How many protons and electrons are in ?Se 78 34 2-

17. P 31 15 3- B 11 5 Au 196 79 Rn 222 86 26 54-26=28 26-2=24 2+00 18-3=15 86

18. 2.5 Different Ions of Some Elements

19. 2.6

20. A molecular formula shows the exact number of atoms of each element in the smallest unit of a substance. An empirical formula tells us which elements are present and the simplest whole-number ratio of the atoms in a substance. H 2 O, N 2 O, CH 4, CH 3 OH, NH 3, CO 2 molecularempirical C 6 H 12 O 6 CH 2 O O3O3 O N2H4N2H4 NH 2 2.6 C6H6C6H6 CH

23. 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 2.6

24. Formula of Ionic Compounds Al 2 O 3 2.6 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 2 x +1 = +21 x -2 = -2 Na + CO 3 2-

26. 1. An anion is defined as A.a charged atom or group of atoms with a net negative charge. B.a stable atom. C.a group of stable atoms. D.an atom or group of atoms with a net positive charge. 2. Atoms of the same element with different mass numbers are called A.ions. B.neutrons. C.allotropes. D.chemical families. E.isotopes. 3. How many neutrons are there in an atom of lead 82 Pb whose mass number is 208? A.82 B.126 C.208 D.290 E.none of them

27. 4. An atom of the isotope sulfur-31 consists of how many protons, neutrons, and electrons? (p = proton, n = neutron, e = electron) A.15 p, 16 n, 15 e B.16 p, 15 n, 16 e C.16 p, 31 n, 16 e D.32 p, 31 n, 32 e E.16 p, 16 n, 15 e 5. A magnesium ion, Mg 2+, has A.12 protons and 13 electrons. B.24 protons and 26 electrons. C.12 protons and 10 electrons. D.24 protons and 22 electrons. E.12 protons and 14 electrons. 6. A sulfide ion, S 2-, has: A.16 protons and 16 electrons B.32 protons and 16 electrons C.16 protons and 14 electrons D.16 protons and 18 electrons E.32 protons and 18 electrons

28. Answer Key 1-A 2-E 3-B 4-B 5-C 6-D Problems 2.10 – 2.11 – 2.12 – 2.14 – 2.16 – 2.18 2.26 - 2.34 – 2.36 – 2.44 – 2.46 – 2.50

29. Chemical Nomenclature Mg(OH) 2 magnesium hydroxide KNO 3 potassium nitrate 2.7 BaCl 2 barium chloride K2OK2O potassium oxide Ionic Compounds –often a metal + nonmetal –cation (metal),anion (nonmetal) –Binary compounds are compounds formed from just two elements –Ternary compounds are compounds formed from three elements.

30. Chemical Nomenclature of Ionic Compounds Chemical Nomenclature of Ionic Compounds nonmetal (anion) Metal (cation)

31. Metal (cation) Divalent element Monovalent element Lithium (Li + ) Sodium (Na + ) Potassium (K + ) Robidium (Rb + ) Silver (Ag + ) Magnisium (Mg 2+ ) Calcium (Ca 2+ ) Strontium (Sr 2+ ) Barium (Ba 2+ ) Lead (Pb 2+ ) Zinc (Zn 2+ ) trivalent element Aluminium (Al 3+ ) Galium (Ga 3+ ) Transition metals (Fe 2+ ) iron(II) (Fe 3+ ) iron(III) (Cr 3+ ) chromium (III) (Cu 2+ ) cupper (II) (Cu + ) cupper (I) (Mn 2+ ) manganese(II) (Mn 3+ ) manganese(III) (Mn 4+ ) manganese(IV) (Mn 7+ ) manganese(VII) (Sn 2+ ) stannous or tin(II) (Hg 2 2+ ) mercury(I) (Hg 2+ ) mercury(II)

32. nonmetal (anion)

33. Some common oxygenated anions (SO 4 2- ) sulphate, (SO 3 2- ) sulphite (NO 3 - ) nitrate (NO 2 - ) nitrite (PO 4 3- ) phosphate (PO 3 3- ) phosphite (ClO 4 – ) chlorate (ClO 3 - ) chlorite (HSO 4 - ) hydrogen sulphate or bisulphate (HPO 4 2- ) hydrogen phosphate (CO 3 2– ) carbonate (HCO 3 – ) bicarbonate (H 2 PO 4 - ) dihydrogen phosphate

34. 2.7

35. 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 2.7 Transition metal ionic compounds –indicate charge on metal with Roman numerals –In the Stock system the different cations charge are designated with Roman numerals

37. Name the following ionic compounds: Cu(NO 3 ) 2 KH 2 PO 4 NH 4 SCN H2O2H2O2 Li 2 SO 3 Ca 3 (PO 3 ) 2 KMnO 4 Cupper(II)nitrate Potassium dihydrogen phosphate Ammonium thiocyanate Hydrogen peroxide Lithium sulphite Calcium phosphite Potassium permenganate Hg 2 Cl 2 Mercury(I)chloride K 2 CrO 4 Potassium chromate

38. Write formulas for the following ionic compounds: MnO K 2 HPO 4 NH 4 ClO 2 Pb(OH) 2 NaHCO 3 Ba(CN) 2 RbHSO 4 HgBr 2 Manganese(II)oxide Potassium hydrogen phosphate Ammonium chlorite Lead hydroxide Sodium bicarbonate Barium cyanide Rubidium hydrogensulphate Mercury(II)bromide SrH 2 Strontium hydride

39. Molecular Compounds 1- Consists of (metalloids + nonmetals) Or (nonmetal + nonmetal) DiboraneB2H6B2H6 MethaneCH 4 SilaneSiH 4 AmmoniaNH 3 PhosphinePH 3 WaterH2OH2O Hydrogen sulfideH2SH2S 2- common names of some molecular compounds 6- last element ends in -ide

40. 2.7 3- element further left in periodic table is 1 st (HCl) H(1A) and Cl(7A), so hydrogen is 1 st, the name is hydrogen chloride 4- element closest to bottom of group is 1 st (SiC) Si(4A) and C also belongs to (4A),but (Si) is closest to bottom of the group, so silicon is 1 st, the name is silicon carbide 5- if more than one compound can be formed from the same elements, use prefixes to indicate number of each kind of atom. (NO) nitrogen monooxide (NO 2 ) nitrogen dioxide (N 2 O) dinitrogen monooxide

41. HIhydrogen iodide PF 3 phosphorus trifluoride H2O2H2O2 Hydrogen peroxide N2O4N2O4 dinitrogen tetraoxide NO 2 nitrogen dioxide N2ON2Odinitrogen monooxide Examples of Molecular Compounds 2.7 TOXIC ! Laughing Gas

42. Name the following molecular compounds: NO 2 SiCl 4 IF 7 P 4 O 10 Cl 2 O 7 CH 4 CS 2 Nitrogen dioxide Silicon tetrachloride Iodine heptaflouride Tetraphosphorus decoxide Dichloro heptoxide Methane Carbon disulphide

43. Write formulas for the following molecular compounds: SF 4 N2O5N2O5 SO 3 Si 2 Br 6 PCl 5 P 4 S 10 N2O2N2O2 Sulphur tetraflouride Dinitrogen pentoxide Sulfur trioxide Disilicon hexabromide Phosphorus pentachloride Tetraphosphorus decasulphide Nitrogen peroxide COCarbon monoxide

44. 2.7

45. Fill the blanks in the following table nameformulaanioncation Barium bicarbonateBa(HCO 3 ) 2 HCO 3 - Ba 2+ Iron(III)nitriteFe 2 (NO 2 ) 3 NO 2 - Fe 3+ Hyrdogen flourideHFF-F- H+H+ Manganise(IV)oxideMnO 2 O 2- Mn 4+ Sodium peroxideNa 2 O 2 O 2 2- Na + Cesium chlorateCsClO 3 ClO 3 - Cs + Lithium nitrideLi 3 NN 3- Li +

46. Answer Key 7-A 8-D 9-C 10-C Problems 2.58 – 2.60 – 2.94