1. 3-1 Inside Atoms Pages 76-80

2. nucleus p 76 central core of an atom containing protons and usually neutrons

3. nucleus

5. proton p.76 small positively charged particle in the nucleus of an atom

7. proton

11. small uncharged (neutral) particle in the nucleus of an atom neutron p 76

14. neutron

16. electron p 76 a tiny, negatively charged, high-energy particle that moves in the space outside the nucleus of an atom

17. electron

21. Let’s review your answers!

22. Yes No

23. Yes No

24. Yes No Yes

25. atomic number p 77 the number of protons in the nucleus of an atom

26. atomic number

28. mass number p 266 mass number = protons + neutrons also called atomic weight

29. What is the mass number?

31. atomic mass unit (amu) p 77 a unit of measurement for the mass of particles in atoms

32. atomic mass unit (amu) The mass of a proton or a neutron = 1 atomic mass unit 1 neutron = 1 amu 1 proton = 1 amu

33. atomic mass unit (amu)

34. How many atomic mass units?

36. valence electrons p 79 the electrons that are farthest away from the nucleus of an atom and involved in chemical reactions (the # of electrons in the outer-most orbital)

37. How many valence electrons?

40. electron dot diagram p. 80 a representation of the number of valence electrons in an atom using dots placed around the symbol of an element

41. electron dot diagrams

42. Turn to page 80 Draw the electron dot diagrams for Carbon and Neon in your notes

43. electron dot diagrams

44. isotopes p 266 an atom with the same number of protons, but a DIFFERENT number of NEUTRONS from other atoms of the same element

45. Isotope

46. isotopes

49. atomic mass/average atomic massp 82 atomic mass (average atomic mass) is the AVERAGE mass (p + n) of an element’s atoms

50. atomic mass/average atomic mass atomic mass/ atomic weight

51. atomic mass/atomic weight vs. mass number atomic mass/atomic weight - average mass for a large group of the same kind of atoms mass number - # of protons + neutrons for 1 specific atom