This document defines and describes subatomic particles like protons, neutrons, and electrons. It explains that atoms are made up of these subatomic particles, with protons and neutrons located in the atomic nucleus and electrons in orbitals outside the nucleus. The document also discusses atomic number, mass number, and isotopes, providing examples of writing out the number of protons, neutrons, and electrons for different atoms and ions.

1. Notes: Subatomic Particles CW: Graphic Organizer H: An Atom

2. Subatomic Particles December 8, 2008

3. Objectives Describe three subatomic particles Define amu, atomic mass, atomic number, isotope

4. 1. The Latin word atomos , is the basis for the word atom. What does the word atomos mean? nucleus indivisible small

5. 2. Indirect evidence about an object is evidence gathered A. by reading a textbook B. using your senses C. without any experimenting

6. 3. Rutherford’s model of the atom is similar to A. the solar system B. raw chocolate chip cookie dough C. a peach

7. What is an atom? the smallest unit of matter that keeps the identity of the element

9. Nucleus Electron Cloud 3 subatomic particles

10. Protons Positive charge Found in the nucleus Mass of 1 AMU (atomic mass unit)

11. Atomic Number This number indicates the number of protons in an atom The number of protons identifies the atom.

12. Neutrons No charge Found in the nucleus Mass of 1 AMU (atomic mass unit)

13. Mass Number = protons + neutrons © Addison-Wesley Publishing Company, Inc.

14. Isotopes Atoms of the same element with different mass numbers. Hyphen notation: carbon-12 Mass # Atomic #

15. It’s the Isotopes!

16. Periodic Table

17. Electrons Negative Charge Found in energy levels outside the nucleus Mass of 1/1836 AMU (almost nothing!)

18. Ion Neutral atom - The number of electrons = number of protons. Ion - The number of electrons is different from the number of protons. (charged atom)

19. PRACTICE PROBLEMS 15 N # protons = ____ # neutrons = ____ # electrons = ___ 35 P # p = ____ # n= ____ #e- = ___ 62 Cu 2+ # p = ____ # n= ____ #e- = ___ 76 Se 3- # p = ____ # n= ____ #e- = ___ 7 8 7 15 20 15 29 33 27 34 42 37

20. Learning Check Naturally occurring carbon consists of three isotopes, 12 C, 13 C, and 14 C. State the number of protons, neutrons, and electrons in each of these carbon atoms . 12 C 13 C 14 C 6 6 6 #p _______ _______ _______ #n _______ _______ _______ #e _______ _______ _______

21. Solution 12 C 13 C 14 C 6 6 6 #p 6 6 6 #n 6 7 8 #e 6 6 6

22. Quick Review: The three subatomic particles are proton, neutron and electron Protons are positively charged, electrons are negative, neutrons are neutral When an electron is lost or gained, the atom becomes an ion.