Section 2.1 The Structure of the Atom

1. Section 2.1 The Structure of the Atom

2. In this section… • The components of an atom • Atomic symbols • Isotopes and atomic weight The Structure of the Atom

3. Components of an Atom: The Structure of the Atom

4. Components of an Atom: The Structure of the Atom

5. The Structure of the Atom

6. Atomic number and mass number: The Structure of the Atom

7. Atomic symbols: The Structure of the Atom

8. Isotopes: atoms with the same number of protons but different numbers of neutrons The Structure of the Atom

9. Isotopes and average atomic weight: The average atomic weight of an element depends on the mass of the atoms but also on the relative abundance of each isotope. The Structure of the Atom

10. Average atomic weights are shown on periodic table: The Structure of the Atom

11. Chiuaua: 4 lbs. Mastif: 120 lbs. What is the average weight of a collection of these dogs?

13. Isotopes and average atomic weight: Average dog mass: 96 % Chiuauas @ 4 lbs. 4 % Mastifs @ 120 lbs. The Structure of the Atom

14. Elements with a single isotope have atomic weight = mass of that isotope Can make rough estimate of relative abundance from average atomic weight. The Structure of the Atom

16. Isotope trends among the elements:

17. Isotopes and average atomic weight: how do we know all this? The Structure of the Atom Mass spectrometry

18. Section 2.2 Elements and the Periodic Table

19. In this section… • Structure of the periodic table • Classifications of elements • Element structures (atomic arrangements) The Periodic Table

21. Periodic table structure: groups (columns)

23. Periodic table structure: periods (rows)

24. Periodic table structure: main group elements

25. Periodic table structure: transition metals

26. Periodic table structure: lanthanides and actinides

27. Periodic table structure: lanthanides and actinides

28. Periodic table structure: lanthanides and actinides

29. Classification of elements:

30. Periodic trends: density

31. Periodic trends: melting point

32. Element structures

33. Element structures: extended structures

34. Element structures: allotropes (same element, different structures)

35. Section 2.3 Covalent Compounds

36. In this section… • The nature of covalent compounds • Ways of representing covalent compounds • Naming covalent compounds Covalent Compounds

37. Covalent compounds are composed of atoms of different elements that are bonded together by sharing electrons. Two types: -- molecular compounds -- network covalent compounds Covalent Compounds

38. Molecular compounds: composed of individual molecules containing the same number of atoms Covalent Compounds

39. Molecular compounds: composed of individual molecules containing the same number of atoms Covalent Compounds

40. Molecular compounds: carbondioxide Molecular Compounds

41. Network covalent compounds: A large number of atoms of different elements bonded by shared electrons. Each sample has molecules with different numbers of atoms. Covalent Compounds

42. Network covalent compounds: silicondioxide Covalent Compounds

43. Representing compounds: Molecular formula: depicts number of atoms of each element Empirical formula: shows simplest integer ratio of atoms of each element Structural formula: shows atomic linkages Models: show 3-dimensional shape of molecule Covalent Compounds

44. Molecular formula: depicts number of atoms of each element Covalent Compounds

45. Empirical formula: shows simplest integer ratio of atoms of each element Covalent Compounds molecular formula: empirical formula:

46. Molecular and Empirical formulas are often the same. Covalent Compounds

47. Structural formula: shows connections between atoms Covalent Compounds

48. Condensed structural formula: mainly for organics. Covalent Compounds CH3CH2CH2CH2OH

49. Models: show 3-dimensional shape Covalent Compounds ball-and-stick wedge-and-dash

50. Models: Ball-and-Stick vs. Space Filling Covalent Compounds