Presentation on theme: "Hope you had a great weekend!"— Presentation transcript:
1Hope you had a great weekend! Test on Friday – Start studying a little each night.Isotopes are atoms of the same element with different numbers of _________ which results in different _______ numbers.What are three isotopes of Hydrogen?When you’re done with the warm-up, look over the element math worksheet from last Thursday because we’re going to start class with a quiz.
2Unit Two, Day Three Kimrey 10 September 2012 Chemistry!!Unit Two, Day ThreeKimrey10 September 2012
3Suppose that there were two isotopes of Sodium. 28% of the naturally occurring sodium atoms had a mass of 22,and 72% atoms had a mass of 23.What would the average atomic weight of sodium be?
428% = .2872% = .72(.28 x 22 ) + (.72 x 23 ) =22.72 amu
5Suppose that there were two natural isotopes of Copper. 80% of the atoms had a mass of 63,and 20% of the atoms had a mass of 65.What would the average atomic weight of copper be?
680% = .8020% = .20(.80 x 63) + (.20 x 65) =63.4 amu
7Suppose that a new element (E) were discovered that existed as three natural isotopes. 25% of the atoms had a mass of 278,38% had a mass of 281,and the remainder had a mass of 285.What would be listed as the atomic weight of this element?
825% = .2538% = .38100% - (25% + 38%)37% = .37(.25 x 278) + (.38 x 281) + ( .37 x 285) =amu