Key Terms: Nucleons Atomic Number Isotope Atomic Mass
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
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)
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
Mass spectrometry is a method for seeing isotopes and their respective ratios (CuI) 3
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
Write the following elements in the opposite notation given. 1.Copper-63 63 Cu 2. 7 Li Lithium-7 3.Silver-108 108 Ag Ne Neon-22
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
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
Average of the masses of all element’s isotopes How do we arrive at 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
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
For carbon there are 2 predominate isotopes: ◦ 12 C at 98.9% abundance ◦ 13 C at 1.1% abundance Molar Mass = 12* *0.011 Molar Mass = Molar Mass = g/mol
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* * * Molar Mass = Molar Mass = 39.1 g/mol
Isotopes of Silver are: ◦ 107 Ag at % abundance ◦ 109 Ag at % abundance Molar Mass = 107* * Molar Mass = Molar Mass =
ParticleChargeMassLocation Proton+11 amuNucleus NeutronNeutral1 amuNucleus Electron0Electron cloud
Number of protons? ◦ 26 Number of electrons? ◦ 26 Number of neutrons? ◦ 30
Number of protons? ◦8◦8 Number of electrons? ◦8◦8 Number of neutrons ◦8◦8