1. Atoms and Elements By Jose Andres Hernandez- Godoy and Mr. Lin

2. Atomic Vocabulary Ion: A charged atom. Not neutral. There is either more electrons than protons or more protons than electrons. This does not change the element because the same amount of protons exist. –Hydrogen with one proton and one electron is neutral but is not stable. A stable Hydrogen will have two electrons, making it a negative ion. Isotope: An atom with more or less neutrons. As a result, the atomic mass is affected, but not its atomic number.

3. N N P P e e This is an example of Helium (He). Its atomic mass is 4.002 AMU 2 Protons = 2 AMU 2 Neutrons = 2 AMU The remaining 0.002 refer to the mass of the electrons 2 He 4.002

4. 3 Li 6.941 P P P N N N e e e This is an example of Lithium (Li). Its atomic mass is 6.941 AMU 3 Protons = 3 AMU 3 Neutrons = 3 AMU The remaining 0.941 refer to the mass of the electrons

5. P 5 B 10.811 P P P P N N N N N e e e e e This is an example of Boron (B) Its atomic mass is 10.811 AMU 5 Proton= 5 AMU 5 Neutrons = 5 AMU The remaining 0.811 refer to the mass of the electrons

6. P 1 H 1.00794 This is an example of Hydrogen (H) Its atomic mass is 4.002 AMU 1 Protons = 1 AMU 0 Neutrons = 0 AMU The remaining 0.00794 refer to the mass of the electron e

7. Atoms Protons: Positive charge Electrons: Negative charge Neutron: No charge Nucleus: Middle clump of protons and neutrons. Image Courtesy of http://tharkad.pa.msu.edu/~asteiner/wp- content/uploads/atom_model_03.gif

8. P P P P P N N N N N N 6 C 12.0107 e e e e e e This is an example of Carbon (C) Its atomic mass is 12.0107 AMU 6 Proton= 6 AMU 6 Neutrons = 6 AMU The remaining 0.00674 refer to the mass of the electrons P

9. Stable Atoms An atom will be stable if only its outer shell is completely full. –Hydrogen is not stable because it has only one electron in a shell that can hold up to two electrons. –Lithium is not stable because it has only 1 electron in an outer shell that can hold up to eight electrons. Hydrogen would typically like to gain an electron to fill up its outer shell. Lithium would typically like to lose an electron to have a full outershell.

10. Ionic Bond When a Hydrogen atom meets a Lithium atom, the Lithium atom will lose its outer electron to the Hydrogen. –Neither atom will have a neutral charge. Hydrogen will have a negative charge now because it now will have more electrons than protons. Lithium will have a positive charge now because it now will have more protons than electrons. The next slide demonstrates an ionic bond

11. P e P P P N N N e e e

12. P e P P P N N N e e e I’m stable! Me too!

13. Covalent Bond When two atoms share possession of electrons, they bind in a covalent bond. When two Hydrogen atoms meet, neither want to give up an electron, but both would like to gain an electron. –As a result, they will “share” their electrons.

14. P e P e

15. P e P e We Are Stable Together !