Ch. 2 - Atomic Structure

1. Ch. 2 - Atomic Structure I.Subatomic Particles II. The Periodic Table

2. QUARKS equal in a neutral atom Atomic Number equals the # of... Most of the atom’s mass. Subatomic Particles ATOM NUCLEUS ELECTRONS NEUTRONS PROTONS NEGATIVE CHARGE POSITIVE CHARGE NEUTRAL CHARGE

3. Subatomic Particles (Parts of the Atom) Particle Symbol Charge Relative Mass Electron e- - 0 amu Proton p+ + 1 amu Neutron n0 0 1 amu

4. Location of Subatomic Particles Electron (-) Nucleus Proton (+) Neutron

5. Atoms Family Album Click on the Light Bulb to See the Atoms Family Album

6. Atoms are building blocks of elements. • Each element is made of only one type of atom. • Example: Aluminum is made only of aluminum atoms.

7. Each element’s atoms are different from atoms of other elements. • Example: Aluminum’s atoms are different from copper’s atoms.

8. Atomic Number The number of protons in the atom. (If the atom is neutral, it is also the number of electrons.)

9. Atomic Number Symbol Atomic Number on the Periodic Table 6 C

10. 6 protons Carbon All atoms of an element have the same number of protons! 6 C

11. Learning Check State the number of protons (or electrons) for atoms of each of the following: 1. Nitrogen A) 5 B) 7 C) 14 2. Sulfur A) 32 B) 16 C) 6 3. Barium A) 137 B) 81 C) 56

12. Mass Number Counts the number of protons plus neutrons in an atom, so to find the number of neutrons you simply use this formula: Mass # - Atomic # = # of neutrons

13. Atomic Number Mass Number Atomic Symbols • Show themass number and atomic number • Give the symbol of the element 6 C 12

14. Number of Electrons • An atom is neutral • The net charge is zero • Number of protons = Number of electrons • Atomic number = Number of electrons

15. Subatomic Particles in Some Atoms 815 30 OP Zn 16 3165 8 p+15 p+30 p+ 8 e-15e-30 e- 8 n16 n 35 n

16. Drawing Atomic Models • The first electron shell/level/cloud can hold 2 electrons • The second electron shell/level/cloud can hold 8 electrons • The third electron shell/level/cloud can hold 18 electrons • The neutrons and protons are in the nucleus (center)

17. 6 C 12 Let’s draw a model for sodium (Na) • How many protons does it have? • 6 (same as atomic number) • How many neutrons? • 6 (atomic mass - atomic number = 12 - 6 = 6) • How many electrons? • 6 (same as # of protons)

18. Where do we put this stuff? • 6 protons, 6 neutrons, 6 electrons • Protons and neutrons go in the nucleus • Electrons go in the orbitals/shells/clouds

19. How many electrons fit in the first shell? How many electrons fit in the second shell? How many electrons fit in the third shell? e- 6 p+ 6 n0 e- e- e- e- e- Protons and neutrons go in the nucleus

20. Examples of 3-d Bohr Models • Visionlearning

21. The Elements Song

22. • • C Lewis Dot Structure • •

23. • • • C • What does this symbol mean? Carbon Dots tell you valence electrons

24. • • C • Valence Electrons? Valence electrons are electrons in the outermost shell of an atom. They are involved in forming bonds with other elements. •

25. 6 C 12 How do you figure out valence electrons? Protons? 6 (same as atomic number) Neutrons? 6 (atomic mass - atomic number) Electrons? 6 (same as atomic number)

26. So we know carbon has 6 electrons…now what? e- The first shell holds 2. Now 4 are left. They go in the second shell. e- 6p+ 6n e- e- e- How many are in the outermost shell? e- 4!

27. • • C • • 4 valence electrons=4 dots!

28. How to draw your dots… • • Chlorine has 7 valence electrons. First put dots on each side before you double up. • • 6 2 Cl • • 3 1 • 7 5 4

29. An Easy Trick! To figure out how many dots to draw 1 2 (1)3 (1)4 (1)5 (1)6 (1)7 (1)8 Exception!

30. • • • • Ne • • • • If an element has a full outermost shell, that means it does not react with anything. Which elements have full outermost shells?

31. Li • • N • • • • • • F • • • • • Ca • • O • • • • • • Now you try… Lithium Nitrogen Calcium Oxygen Fluorine