2.  Proton  Neutron  Electron

4. Positive Charge Mass of 1 atomic mass unit (amu) Found in the nucleus Equal to the atomic Number Determines the element Remember PP (Protons are positive)

5. No charge Mass of 1 amu Found in the nucleus Number of neutrons + number of protons = mass number To get the number of neutrons, mass number – atomic number Remember NN (No charge on Neutrons)

6. Negatively charged No mass Found in the electron cloud In a neutral atom = equal to the number of protons

7. The nucleus is the central part of an atom. It is composed of protons and neutrons. The nucleus contains most of an atom's mass. It was discovered by Ernest Rutherford in 1911.

8. ElementSymbolAtomic Number Mass Number Number of Protons Number of Neutrons Number of Electrons Calcium Boron Zn Rh 41 35 Sodium

9. http://www.eskom.co.za/nuclear_energy/fuel/fuel.html

10. See more diagrams at: http://www.bmb.psu.edu/courses/bisci004a/chem/basechem.htm http://www.bmb.psu.edu/courses/bisci004a/chem/basechem.htm

11. http://www.bmb.psu.edu/courses/bisci004a/chem/atoms.jpg

12. Atoms that have the same number of protons but different numbers of neutrons

13. Example: http://education.jlab.org/glossary/isotope.html

14. Model of the atom pictures the electrons moving around the nucleus in a region called an electron cloud. The electron cloud is a cloud of varying density surrounding the nucleus. The varying density shows where an electron is more or less likely to be. Atoms with electrons in higher energy levels have additional electron clouds of different shapes that also show where those electrons are likely to be. For more information, click here: http://regentsprep.org/Regents/physics/phys05/catomodel/cloud.htm