CHEM 101 1nd Edition Lecture 5 Outline of Last Lecture I. RadioactivityII. About AtomsIII. IsotopesIV. Counting AtomsOutline of Current Lecture I. MoleII. Periodic Table of the ElementsCurrent LectureV. Molea. Using Avogadro's Numberb. Examplesi. Look up Ni on the periodic table1. Thus 1 atom of Ni has a mass of 58.69 amu2. and 1 mol of Ni atoms has a mass of 58.69 g3. Should be thinking (g/mol) as units for the atomic weights listed inthe periodic tableii. How many moles of Mg are represented by 0.200 g? How many atoms?1. How many moles?a. 0.200 g x (1 mol/24.31 g) = 8.23 x 10-3 mol2. How many atoms?a. 8.23 x 10-3 mol x (6.022 x 1023 atoms/1 mol) = 4.95 x 1021 atoms of Mgiii. What is the identity of an element if 2.42 moles of it weight 65.4 g?1. 65.4 / 2.42 = 27.0, Al = 26.982. How to:a. Plan: have mol and g; want to figure out atomic weight andthen use the periodic table to identify the elementb. Atomic weight has units g/moli. We can use it as a formulac. 65.4 g / 2.42 mols = 27.0 g/mol = atomic weightiv. Calculate the mass of an atom of FeThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.1. 1 mol of Fe has a mass of 55.85 g, 1 mold of Fe contains 6.022 x 10232. (55.35 g/1 mol) x (1 mol/6.022 x 1023 atoms) = 9.274 x 10-23v. How many moles of Hg and how many atoms of Hg are contained in 9.84 mL of Hg? Density is 13.5931. 1 mol hof Hg has a mass of 200.59 g, 1 mol contains 6.022 x 1023 atoms2. Usual plan of attack: g -> moles -> atomsa. Have to convert mL to g3. Revised: mL -> g-> moles -> atoms4. 9.84 mL x (1 cm3/1mL) x (13.5939 g/cm3) = 133.763976 g5. 133.763976 g x (1 mol/200.59 g) = 0.66685266 mol, = 0.667 mol6. 0.66685266 mol x (6.022 x1023/1 mol) = 4.0157867 x 1023 atoms, = 4.02 x 1023 atomsvi. Two moles of silicon dioxide would have a mass of?1. (15.999 x 2) + 28.085 = 60.083 g x 2 = 120.16 gvii. How many atoms are in 14.0 g of 46Ca1. 14.0 g / 46 = .30434783 mol x 6.022 x 1023 = 1.83 x 1023 VI. Periodic Table of the Elementsa. Dmitri Mendeleeve developed the modern period tablei. Argued that element properties are periodic functions of their atomic weightsb. A systematic catalog of elementsc. Elements are arranged in order of atomic numberd. Rows are called periode. Columns are called groupf. Characteristics of metali. High electrical conductivityii. All are solids, except Hg, at room temperatureiii. Form cations and losing electronsiv. Form ionic compound with nonmetalsg. Characteristics of nonmetalsi. Poor electoral conductivityii. Gases, liquids or solids at room temperatureiii. Form anions by gaining electronsiv. Form covalent complexes with other
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