3. Vocabulary ATOM-An atom is the smallest unit that maintains the characteristics of an element – Nucleus- The center of the atom, contains protons and neutrons – Electron Cloud –Region surrounding the nucleus containing the electrons ELEMENT- A chemical substance that is composed of atoms with the same number of protons in the nucleus

4. The Atom

6. Nucleus Protons Neutrons

7. http://www.g eocities.com/Y osemite/Rapid s/1111/adams famsong.htm http://www.g eocities.com/Y osemite/Rapid s/1111/adams famsong.htm Chorus: They are so small. (Snap, snap) They’re round like a ball. (Snap, snap) They make up the air. They’re everywhere. Can’t see them at all. (Snap, snap) 2nd Verse: Together they make gases, And liquids like molasses, And all the solid masses, The Atoms Family Chorus: They are so small. (Snap, snap) They’re round like a ball. (Snap, snap) They make up the air. They’re everywhere. Can’t see them at all. (Snap, snap) Chorus: They are so small. (Snap, snap) They’re round like a ball. (Snap, snap) They make up the air. They’re everywhere. Can’t see them at all. (Snap, snap) 1st Verse: They’re tiny and they’re teeny, Much smaller than a beany, They never can be seeny, The Atoms Family. 3rd Verse: Neutrons can be found, Where protons hang around; Electrons they surround The Atoms Family.

8. The Nucleus Proton-A positively charged sub-atomic particle (+). Atomic Mass=1 amu The number of protons is the same as the atomic number Li 3 7 The atomic mass The Atomic Symbol

9. The Nucleus Neutrons –A sub-atomic particle in the nucleus --Has a mass equal to 1 atomic mass unit --Neutron do not have a charge (0) To calculate the number of neutrons in an element… Li 3 7 The atomic number The atomic mass -The atomic number The number of neutrons

10. The Atom

11. The Electron Cloud Electrons- The number of electrons equals the number of protons Sub-atomic particle with a negative charge (-) Mass of an electron is negligible Electrons behave as if in a 3-D orbit Valence Electrons – The outer most electrons – Valence electrons are responsible for bonding

12. Bohr Model The first shell can have 2 electrons The second shell can have 8 electrons

13. Shells and the Electron Cloud

15. Periodic Table Groups- Arranged by the number of valence electrons Each group has similar bonding properties Periods-Arranged by increasing atomic weight Periods have the same number of shells Example:Group 1…1 valence electron Group 2…2 valence electrons Group 3…3 valence electrons Example:Period 1…1 valence shell Period 2…2 valence shells Period 3…3 valence shells

16. Periodic Table Periods go across on the periodic table Periods have the same number of “shells” 1 2 3 4 5 6 7

17. Periodic Table Groups go down on the periodic table Elements in the same group, have the same number of valence electrons 12 34 5687

18. Let’s look at a few elements… Hydrogen 1= Proton1= electron

19. Let’s look at a few elements… Helium 2=protons2=neutrons 2=electrons

20. Let’s look at a few elements… Lithium 3=protons4=neutrons 3=electrons

21. Let’s look at a few elements… Fluorine 9=protons10=neutrons 9=electrons

22. Let’s look at a few elements… Argon 18=protons22=neutrons 18=electrons