Atom basics
- 1. The Atom Atomic Number and Mass Number Isotopes LecturePLUS Timberlake 1
- 2. Atomic Theory Atoms are building blocks of elements Similar atoms in each element Different from atoms of other elements Two or more different atoms bond in simple ratios to form compounds LecturePLUS Timberlake 2
- 4. Location of Subatomic Particles 10-13 cm electrons protons nucleus 10-8 cm LecturePLUS Timberlake neutrons 4
- 5. Atomic Number Counts the number of protons in an atom LecturePLUS Timberlake 5
- 6. Periodic Table Represents physical and chemical behavior of elements Arranges elements by increasing atomic number Repeats similar properties in columns known as chemical families or groups LecturePLUS Timberlake 6
- 8. Atomic Number on the Periodic Table Atomic Number Symbol 11 Na LecturePLUS Timberlake 8
- 9. All atoms of an element have the same number of protons 11 protons Sodium 11 Na LecturePLUS Timberlake 9
- 10. Learning Check AT 1 State the number of protons for atoms of each of the following: A. Nitrogen 1) 5 protons 2) 7 protons 3) 14 protons B. Sulfur 1) 32 protons 2) 16 protons C. Barium 1) 137 protons 2) 81 protons LecturePLUS Timberlake 3) 6 protons 3) 56 protons 10
- 11. Solution AT 1 State the number of protons for atoms of each of the following: A. Nitrogen 2) 7 protons B. Sulfur 2) 16 protons C. Barium 3) 56 protons LecturePLUS Timberlake 11
- 12. Number of Electrons An atom is neutral The net charge is zero Number of protons = Number of electrons Atomic number = Number of electrons LecturePLUS Timberlake 12
- 13. Mass Number Counts the number of protons and neutrons in an atom LecturePLUS Timberlake 13
- 14. Atomic Symbols Show the mass number and atomic number Give the symbol of the element mass number 23 atomic number Na sodium-23 11 LecturePLUS Timberlake 14
- 15. More Atomic Symbols 16 31 O 8 8 p+ 8n 8 e- 65 P 15 Zn 30 15 p+ 30 p+ 16 n 35 n LecturePLUS 15 e- Timberlake 30 e- 15
- 16. Masses of Atoms A scale designed for atoms gives their small atomic masses in atomic mass units (amu) An atom of 12C was assigned an exact mass of 12.00 amu Relative masses of all other atoms was determined by comparing each to the mass of 12 C An atom twice as heavy has a mass of 24.00 amu. An atom half as heavy is 6.00 amu. 16 LecturePLUS Timberlake
- 17. Atomic Mass Na 22.99 Listed on the periodic table Gives the mass of “average” atom of each element compared to 12C Average atom based on all the isotopes and their abundance % Atomic mass is not a whole number LecturePLUS Timberlake 17
- 18. Learning Check AT6 Using the periodic table, specify the atomic mass of each element (round to the tenths place): A. calcium __________ B. aluminum __________ C. lead __________ D. barium __________ E. iron __________ LecturePLUS Timberlake 18
- 19. Solution AT6 Using the periodic table, specify the atomic mass of each element (round to the tenths place): A. calcium _40.1 amu _ B. aluminum _27.0 amu _ C. lead _207.2 amu_ D. barium _137.3 amu_ E. iron _55.8 amu__ LecturePLUS Timberlake 19