1. Key Terms: Nucleons Atomic Number Isotope Atomic Mass

2.  Particles in the nucleus of atoms ◦ Protons ◦ Neutrons  These particles are “bound” together to form the dense positively charged nucleus that was discovered by Rutherford’s experiments

3.  Equal the number of protons in the nucleus on an atom  Seen on the periodic table as a whole number  The number or protons determines the identity of the element ◦ 6 protons is a carbon atom  Neutral atom- ◦ Number of protons (positive) = number of electrons (negative)

4.  Atoms of an element that have different numbers of neutrons  For carbon there are 2 predominate isotopes: ◦ 12 C at 98.9% abundance ◦ 13 C at 1.1% abundance  The above notation in known as nuclear symbol notation  There is also hyphen notation ◦ Carbon-12 and Carbon-13

5. Mass spectrometry is a method for seeing isotopes and their respective ratios (CuI) 3

6.  Hydrogen-1 ◦ 1 proton and 0 neutrons  Hydrogen-2 ◦ 1 proton and 1 neutron  Hydrogen-3 ◦ 1 proton and 2 neutrons  What is the nuclear notation for these? ◦1H◦1H ◦2H◦2H ◦3H◦3H

7.  Write the following elements in the opposite notation given. 1.Copper-63  63 Cu 2. 7 Li  Lithium-7 3.Silver-108  108 Ag 4. 22 Ne  Neon-22

8.  Total number of protons and neutrons in an atom  The mass number is always a whole number  Looking at Carbon-12, how many protons and neutrons? ◦ 6 protons and 6 neutrons  Number of neutrons = mass number - protons  Electrons are ignored in mass number calculations because they weigh 1/2000 th of a proton

9.  How many protons and neutrons are in 63 Cu? ◦ Atomic number = 29  number of protons ◦ 63 mass number – 29 protons = 34 neutrons  How many protons and neutrons are in 39 K? ◦ Atomic number = 19  number of protons ◦ 39 mass number – 19 protons = 20 neutrons

10.  Average of the masses of all element’s isotopes  How do we arrive at 12.011 g/mol if protons and neutrons each weigh 1 amu? ◦ The average of all of the abundances of isotopes can be used to calculate the atomic mass of an element

11.  Using isotopes we can solve for the Atomic Mass of an element using the following equation:  (mass of isotope A)(Percent abundance of A) + (mass of isotope B)(Percent Abundance of B) +…. = Molar Mass

12.  For carbon there are 2 predominate isotopes: ◦ 12 C at 98.9% abundance ◦ 13 C at 1.1% abundance Molar Mass = 12*0.989 + 13*0.011 Molar Mass = 11.868 + 0.143 Molar Mass = 12.011 g/mol

13.  Isotopes of potassium are: ◦ 39 K at 93.26% abundance ◦ 40 K at 0.012% abundance ◦ 41 K at 6.73% abundance Molar Mass = 39*0.9326 + 40*0.00012 + 41*0.0673 Molar Mass = 36.37 + 0.0048 +2.759 Molar Mass = 39.1 g/mol

14.  Isotopes of Silver are: ◦ 107 Ag at 51.839% abundance ◦ 109 Ag at 48.161% abundance Molar Mass = 107*0.51839 + 109*0.48191 Molar Mass = 55.4677 + 52.52819 Molar Mass = 107.995

15. ParticleChargeMassLocation Proton+11 amuNucleus NeutronNeutral1 amuNucleus Electron0Electron cloud

16.  Number of protons? ◦ 26  Number of electrons? ◦ 26  Number of neutrons? ◦ 30

17.  Number of protons? ◦8◦8  Number of electrons? ◦8◦8  Number of neutrons ◦8◦8