2. Objectives Explain what isotopes are Define atomic number and mass number, and describe how they apply to isotopes. Given the identity of a nuclide, determine its number of protons, neutrons, and electrons. Define mole in terms of Avogadro’s number, and define molar mass. Solve problems involving mass in grams, amount in moles, and number of atoms of an element
3. Atomic Number Symbol – Z Number of protons in nucleus of atom Determines the identity of the atom!!!!! C - 6 He - ___ F - ___ Pb - ___ Use periodic table to find these! Since atoms are neutral atomic number is also number of electrons So C also has 6 electrons He - ____ electrons
4. Isotopes All Hydrogen atoms contain 1 proton Many naturally occurring elements can contain different numbers of neutrons. Isotope – at0ms of the same element that have different masses. n n n Protium 99.985 % Deuterium 0.015 % Tritium Trace Three isotopes of Hydrogen
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7. A X A : mass number, Z : atomic number, X : symbol of element
16. Copper - 63 69.17% with mass of 62.929599 amu Copper – 65 30.83% with mass of 64.927793 amu (0.6917 x 62.929599 amu) + (0.3083 x 64.927793 amu) =63.55 Match with atomic mass on periodic table Round to two decimal places in calculations
17. Relating Mass to Numbers of Atoms The MOLE SI base unit for amount of a substance Abbreviated as mol Defined as : amount of substance that contains as many particles as there are atoms in exactly 12 g of carbon – 12 Counting unit just like a dozen We don’t order 12 or 24 eggs, we order 1 or 2 dozen In same way, a chemist may want 1 mol of carbon or 2 mol of iron. 63.55 g of copper or 1 mol of copper
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20. Gram/Mole Conversions Mass In grams Moles In mol Atoms In atoms Avogadro’s Number Molar mass What is the mass in grams of 3.50 mol of the element copper, Cu? A chemist produced 11.9 g of Aluminum, Al. How many moles of aluminum were produced? How many moles of silver, Ag, are in 3.01 x 1023 atoms of silver? What is the mass in grams of 1.20 x 1023 atoms of copper, Cu?
21. The Ten Commolements (found at http://members.tripod.com/~smalls42/commolements.html) Thou shalt not use 6.02 x 1023 in vain. Thou shalt not use the term mole if thou has no true knowledge of the term mole. Thou shalt not kill a mole. Thou shalt not covet your neighbor's mole. Thou shall always remember to celebrate Mole Day. Thou shalt not disparage Mole Day. Thou shalt not use a mole out of season. Thou shalt always honor the one who introduced thou to Mole Day. You shalt always keep sacred 10/23. Thou shalt always remember these commolments or thou will never properly celebrate Mole Day.
