3.  Determines the element  Number of protons CANNOT change for an element  Common charge notation is +1  Mass (g) = 1.673 x 10 -24  Mass (amu)= 1.0073 = 1

4.  Common charge notation is 0. No charge!  Mass (g) 1.675 x 10 -24 (same mass as proton)  Mass (amu)= 1.0082 = 1  Number of neutrons CAN change for an element  ISOTOPES  Stabilizes nucleus by nuclear force

5.  Common Charge notation is -1  Mass (g) of e- = 9.109 x 10 -28  Mass (amu)=.0006 = 0  Number of electrons CAN change for an element  IONS  Responsible for chemical reactivity, forms bonds

6. ProtonNeutronElectron LocationNucleus Outside of nucleus Common charge+0_ Mass, g1.673x10 -24 1.675 x 10 -24 9.109 x 10 -24 Mass, amu110

7.  Which subatomic particle can NOT change for an element and gives it’s identity?  Which subatomic particle stabilizes the nucleus?

8.  Atomic Number: The number of protons in each atom of that element.  Unique to EACH element, never changes!!  Neutral atoms: proton #= electron #  Example: 1. How many protons does Beryllium (Be) have? How many electrons? 2. How many protons does Gold (Au) have?

9.  Isotopes: Are atoms that have different number of neutrons  So masses are different Example of isotopes:

10.  Mass Number: The total number of protons and neutrons in the nucleus

11.  Element- Mass number  What is the hyphen notation of lithium if the mass number is 4?

12. Common isotopes of carbon Carbon-12 Carbon-13 Carbon-14 How many protons do all the carbon isotopes have? How many neutrons do each of the carbon isotopes have?

13.  Atoms are Neutral because they have the same number of electrons and protons  You will assume this unless indicated otherwise

14.  Ions :are when the electron number and proton number are different leading to a net charge.  What charge would Aluminum have 13 protons and 10 electrons?  NOTE: YOU WILL ALWAYS ASSUME ATOMS ARE NEUTRAL (protons = electrons) UNLESS TOLD OTHERWISE

15.  Atomic #= Proton #= Electron # (because we assume atoms are neutral)  Mass #= Atomic # + Neutron #

16.  Number of protons= Atomic number  Number of electrons = Number of protons (in a neutral atom)  Number of neutrons = Mass number– Atomic number SymbolAtomic # Mass ## of protons # of electrons # of neutrons Na11 1531

17.  Average atomic mass is the weighted average of the atomic masses of the naturally occurring isotopes of an element  This number appears below the element symbol on the periodic table.