Содержание
- 2. Periodic Table
- 3. Information about an element
- 4. Let’s take Li atom for an example: It has 3 protons, 3 neutrons and 3 electrons.
- 5. Atomic number and Mass Number The number of protons in a given atom is called the
- 6. Atomic number and Mass Number Example: Atomic Number = 17 Mass Number = 36 Neutron number
- 7. Number of electrons An atom is neutral. The net charge is zero. Therefore, Number of protons
- 13. Isotopes同位素 They are atoms of the same element that have different numbers of neutrons. Hydrogen has
- 14. Isotopes Hydrogen has 3 isotopes. Have more neutrons, increases the mass.
- 15. Isotopes Hydrogen has 3 isotopes. Mass number = 1 Mass number = 2 Mass number =
- 16. 6 protons, 8 (14 - 6) neutrons, 6 electrons 6 protons, 5 (11 - 6) neutrons,
- 18. Periodic Table
- 23. Cation and Anion An ion is an atom, or group of atoms, that has a net
- 24. Cation and Anion A monatomic ion contains only one atom eg. Na+, Cl-, Ca2+, O2-, Al3+,
- 25. 13 protons, 10 (13 – 3) electrons 34 protons, 36 (34 + 2) electrons Do You
- 28. ***
- 30. Why does the atomic mass on the periodic table have so many decimal places? 6 C
- 31. Atomic mass 1 H 1.00797 This atomic mass is the one number that best represents the
- 32. Calculating a “weighted” average 1. First, you have to know the mass of each isotope. 2.
- 33. Calculating a “weighted” average A sample of magnesium collected anywhere in the universe will contain three
- 34. Calculating a “weighted” average
- 35. Calculating a “weighted” average Atomic mass of magnesium = 23.985045 x 78.90% + 24.985839 x 10.00%
- 36. For your reference
- 37. Cl-35 is about 75.5 % and Cl-37 about 24.5% of natural chlorine. Another example This atomic
- 38. Exercise Copper has two isotopes 63Cu (62.9 amu) and 65Cu (64.9 amu). What is the %
- 39. Periodic Table
- 41. Periodic Table
- 43. Radioactive isotope Radioactive isotope, also called radioisotope, any of several species of the same chemical element
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