2–1 The Nature of Matter A. Atoms B. Elements and Isotopes 1. Isotopes 2. Radioactive Isotopes

1. Section Outline Section 2-1 • 2–1 The Nature of Matter A. Atoms B. Elements and Isotopes 1. Isotopes 2. Radioactive Isotopes C. Chemical Compounds D. Chemical Bonds 1. Ionic Bonds 2. Covalent Bonds 3. Van der Waals Forces

2. Matter –Anything that has mass and occupies space • 1 The basic unit of matter is called the_____.

3. Matter –Anything that has mass and occupies space • 1 The basic unit of matter is called the atom.

4. Figure 2-2 Isotopes of Carbon Section 2-1 2, 3 Atomic __________________(electron clouds, nuclei) contain _________ and _________. (protons, electrons, neutrons). (+, -, 0)charge size (0.0005 amu, 1 amu) where (nucleus, e cloud) • Protons ___ charge size _____ Where? ________ • Neutrons ___ charge size ____ Where? ________ • Electrons ___ charge size ____ Where? ________ Nonradioactive carbon-12 Nonradioactive carbon-13 Radioactive carbon-14 6 electrons 6 protons 7 neutrons 6 electrons 6 protons 6 neutrons 6 electrons 6 protons 8 neutrons

5. Figure 2-2 Isotopes of Carbon Section 2-1 • 2, 3 Atomic Nuclei contain protons and neutrons. • Protons 1+ charge size 1 amu nucleus • Neutrons 0 charge size 1 amu nucleus • Electrons 1- charge size 1/1840 =0.0005amu el cloud Nonradioactive carbon-12 Nonradioactive carbon-13 Radioactive carbon-14 6 electrons 6 protons 7 neutrons 6 electrons 6 protons 6 neutrons 6 electrons 6 protons 8 neutrons

6. 4 Atoms are neutral because they contain the same # of _________ & protons

7. 4 Atoms are neutral because they contain the same # of electrons & protons.

8. 5 Chemical elements are groups of atoms having the same atomic number, that is, atoms having the same number__________. The number of protons in an atom control its identity as an element.These are all atoms of Carbon. All have atomic #_____.

9. 5 Chemical elements are groups of atoms having the same atomic number, that is, atoms having the same number protons. The number of protons in an atom control its identity as an element. These are all atoms of Carbon. All have atomic # 6.

10. An Element in the Periodic Table Section 2-1 6 • 6. Proton # = 6 : shown by the ____________ number • Also, C atoms have 6 electrons: Since atoms are neutral, if you know proton #, you also know ___________ #! C 12.011

11. An Element in the Periodic Table Section 2-1 6 • 6. Proton # = 6 : shown by the atomic number • Also, C atoms have 6 electrons: Since atoms are neutral, if you know proton #, you also know electron #! C 12.011

12. Figure 2-2 Isotopes of Carbon Section 2-1 • 7 Isotopes are forms of the same element that have the same number of protons but a different number of _____________ (electrons, neutrons). Nonradioactive carbon-12 Nonradioactive carbon-13 Radioactive carbon-14 6 electrons 6 protons 7 neutrons 6 electrons 6 protons 6 neutrons 6 electrons 6 protons 8 neutrons

13. Figure 2-2 Isotopes of Carbon Section 2-1 • 7 Isotopes are forms of the same element that have the same number of protons but a different number of neutrons. Nonradioactive carbon-12 Nonradioactive carbon-13 Radioactive carbon-14 6 electrons 6 protons 7 neutrons 6 electrons 6 protons 6 neutrons 6 electrons 6 protons 8 neutrons

14. Figure 2-2 Isotopes of Carbon Section 2-1 • Isotopes are identified by isotopic notation: Names Carbon-12, carbon-______, carbon-14 OR • 12C C 14C • 6 6 6 Nonradioactive carbon-12 Nonradioactive carbon-13 Radioactive carbon-14 6 electrons 6 protons 7 neutrons 6 electrons 6 protons 6 neutrons 6 electrons 6 protons 8 neutrons

15. Figure 2-2 Isotopes of Carbon Section 2-1 • Isotopes are identified by isotopic notation: Names Carbon-12, carbon-13, carbon-14 OR • 12C 13C 14C • 6 6 6 Nonradioactive carbon-12 Nonradioactive carbon-13 Radioactive carbon-14 6 electrons 6 protons 7 neutrons 6 electrons 6 protons 6 neutrons 6 electrons 6 protons 8 neutrons

16. 9 Isotopes of the same element have the same properties because they have the same atomic number--the same number ___________(electrons, neutrons, protons). For C isotopes, this is _____ . • 12C13C14C • 6 6 6

17. 9 Isotopes of the same element have the same properties because they have the same atomic number (the same number protons). For C isotopes, this is six protons. • 12C13C14C • 6 6 6

18. 10 Chemical compounds are groups of atoms held together by chemical ________. Chemical compounds are more stable than individual atoms (except for n_______ gas atoms like Ne or Xe) which have stable –filled—valence electron shells. • Chemical compounds allow atoms to obey the “_________ rule”. (2 electrons in the outer electron shell in H and He, but 8 for other elements.)

19. 10 Chemical compounds are groups of atoms held together by chemical bonds. Chemical compounds are more stable than individual atoms (except for noble gas atoms which have stable ---filled—valence electron shells. • Chemical compounds allow atoms to obey the “octet rule”. (2 electrons in the outer electron shell in H and He, but 8 for other elements.

20. 11 The position of an element in a group/family—column—of the periodic table reveals it # valence or ___________ (lowest, highest) energy level electrons. These valence electrons control its chemical reactions. Members of family 16 have ___ valence electrons.

21. 11 The position of an element in a group/family—column—of the periodic table reveals it # valence or highest energy level electrons. These valence electrons control its chemical reactions. Members of family 16 have 4 valence electrons.

22. 12 The periodic table row (period) of an element reveals which of its energy levels is its valence shell. The valence shell for H is the ____ (1st, 2nd, 3rd) energy level, but for Al, it’s the ______, while for C it’s the _____.

23. 12 The periodic table row (period) of an element reveals which of its energy levels is its valence shell. The valence shell for H is the 1stenergy level, but for Al, it’s the 3rd, while for C it’s the 2nd.

24. 13 Pure elements are rare because most atoms under chemical reactions to attain a valence energy level octet. Carbon C and other members of family 16 have _____ valence electrons, but to be stable they need ______ more valence electrons. Oxygen O and other members of family 17 have _____ valence electrons, but to be stable, they need _________ more valence electrons.

25. 13 Pure elements are rare because most atoms under chemical reactions to attain a valence energy level octet. Carbon C and other members of family 16 have four valence electrons, but to be stable they need four more valence electrons. Oxygen O and other members of family 17 have seven valence electrons, but to be stable, they need one more valence electron.

26. 14 C_________ f_________ show the numbers of different kinds of atoms bonded together in a single formula unit of a compound • Al2O3 2 Al ions bonded to 3 O ions • NaCl ______ Na ion bonded to one Cl ion • Why do we know it’s composed of ions? Because Na is a _______—an electron donor—and Cl is a __________—an electron acceptor –If a metal is present to give it an electron.

27. 14 Chemical formulas show the numbers of different kinds of atoms bonded together in a single formula unit of a compound • NaCl one Na ion bonded to one Cl ion • Why do we know it’s composed of ions? Because Na is a metal—an electron donor—and Cl is a nonmetal—an electron acceptor if a metal is present to give it an electron.

28. 15 Atoms in compounds are held together by chemical bonds—either i______ or c_______.Covalent compounds

29. 15 Atoms in compounds are held together by chemical bonds—either ionic or covalent.

30. Figure 2-3 Ionic Bonding 16 Ionic bonds: attraction of negative ions to positive ions because a metal donates its __________ to a nonmetal atom, forming stable ions with complete _________ shell octets. Section 2-1 Sodium ion (Na+) Chloride ion (Cl-) Sodium atom (Na) Chlorine atom (Cl) Transfer of electron Protons +11 Electrons -11 Charge 0 Protons +17 Electrons -17 Charge 0 Protons +11 Electrons -10 Charge +1 Protons +17 Electrons -18 Charge -1

31. Figure 2-3 Ionic Bonding 16 Ionic bonds: attraction of negative ions to positive ions because a metal donates its electrons to a nonmetal atom, forming stable ions with complete valence shell octets. Section 2-1 Sodium ion (Na+) Chloride ion (Cl-) Sodium atom (Na) Chlorine atom (Cl) Transfer of electron Protons +11 Electrons -11 Charge 0 Protons +17 Electrons -17 Charge 0 Protons +11 Electrons -10 Charge +1 Protons +17 Electrons -18 Charge -1

32. 17 _________ bonds form when nonmetal atoms share electrons to fill their valence o_______, linking atoms because both nuclei attract the shared electrons. The dots around the nuclei of each atom represent ___________ __________. The dots in between two nuceli in the formulas are ________________ by the two atoms. The formulas for the c_________ compounds formed below are _____, ______, ______, and ________.

33. 17 Covalent bonds form when nonmetal atoms share electrons to fill their valence octets, linking atoms because both nuclei attract the shared electrons. The dots around the nuclei of each atom represent valence electrons. The dots in between two nuceli in the formulas are shared by the two atoms. The formulas for the covalent compounds formed below are H2, F2, CO2, and CF4.

34. Figure 2-3 Ionic Bonding 18 _____are atoms carrying a charge after losing or gaining valence electrons. Section 2-1 Sodium atom (Na) Chlorine atom (Cl) Sodium ion (Na+) Chloride ion (Cl-) Transfer of electron Protons +17 Electrons -18 Charge -1 Protons +11 Electrons -11 Charge 0 Protons +11 Electrons -10 Charge +1 Protons +17 Electrons -17 Charge 0

35. Figure 2-3 Ionic Bonding 18 Ions are atoms carrying a charge after losing or gaining valence electrons. Section 2-1 Sodium atom (Na) Chlorine atom (Cl) Sodium ion (Na+) Chloride ion (Cl-) Transfer of electron Protons +17 Electrons -18 Charge -1 Protons +11 Electrons -11 Charge 0 Protons +11 Electrons -10 Charge +1 Protons +17 Electrons -17 Charge 0

36. 19. True orFalse. ______Atom that loses electrons becomes a positive ion. (sodium atoms have 11 protons in the nucleus and 11 neutrons and 11 electrons. Sodium ions have 11 protons, 11 neutrons, and 10 electrons).

37. 19True orFalse. True_Atom that loses electrons becomes a positive ion. (sodium atoms have 11 protons in the nucleus and 11 neutrons and 11 electrons. Sodium ions have 11 protons, 11 neutrons, and 10 electrons). Sodium Chlorine sodium ion chlorine ion atom Na atom Cl Na1+ Cl1-

38. 20. True orFalse. _________Nonmetal atoms that gain electrons becomes positive ions. (chlorine atoms have 17 protons in the nucleus and 18 neutrons and 11 electrons. Chlorine ions have 17 protons, 18 neutrons, and 18 electrons). Sodium Chlorine sodium ion chlorine ion atom Na atom Cl Na1+ Cl1-

39. 20. FALSE Nonmetal atoms that gain electrons becomes positive ions. (chlorine atoms have 17 protons in the nucleus and 18 neutrons and 11 electrons. Chlorine ions have 17 protons, 18 neutrons, and 18 electrons). Sodium Chlorine sodium ion chlorine ion atom Na atom Cl Na1+ Cl1-

40. 21. When ionic compounds form, _______ (metals or nonmetals) lose electrons to become __________ (negative or positive) ions because they have ______ (lower or higher) electronegativity than the __________(metals or nonmetals) which take the electrons to become ____________(negative or positive) ions. Na Cl Na1+ Cl1-

41. 21. When ionic compounds form, metals lose electrons to become positive ions because they have lower electronegativity than the nonmetals which take the electrons to become negative ions. Metals nonmetalsNa Cl Na1+ Cl1-

42. 17 M__________ (Not ionic compounds!) form when atoms are joined with covalent bonds.Covalent bonds form when nonmetals react together. These bonds form between two atoms sharing electrons.

43. 17 Molecules (Not ionic compounds!) form when atoms are joined with covalent bonds.

44. 18 _____ (1, 2, 3, 4, 5, 6, 7 or 8) shared electrons between 2 atoms forms a single covalent bond. ___ (1, 2, 3, 4, 5, 6, 7 or 8) shared electrons is a double covalent bond. _____ (1, 2, 3, 4, 5, 6, 7 or 8) shared electrons is a triple covalent bond http://academic.brooklyn.cuny.edu/biology/bio4fv/page/covalent_bonds.html

45. 18 Two shared electrons between 2 atoms forms a single covalent bond. Four shared electrons is a double covalent bond. Six shared electrons is a triple covalent bond http://academic.brooklyn.cuny.edu/biology/bio4fv/page/covalent_bonds.html

46. 19. In covalent compounds, electrons are shared equally in each covalent bond if the atoms have similar electronegativity.

47. 19 Van Der Waals forces for nonpolar covalent compounds and dipole-dipole interactions for polar covalent compounds hold atoms of nearby molecules together. • Occasionally, valence electrons are nearer one atom than the other in a covalent bond, creating areas partial charge. http://www.chem.unsw.edu.au/coursenotes/CHEM1/nonunipass/HainesIMF/images/dipoledipole.jpg