Name: Gavenjit Dhesi Block: Mrs. Wong Isotope Quiz 1. 2. Here are three isotopes of an element: 312 A< a. The element is: Argon b. The number 18 refers to the Atomic number c. The numbers d. How many protons and neutrons are in the first isotope? 18 protons and 18 neutrons (36-18 = 18) e. How many protons and neutrons are in the second isotope? 18 protons and 20 neutrons (38-18 = 20) f. How many protons and neutrons are in the third isotope? 18 protons and 22 neutrons (40-18 = 20) Com 36, 38, lete the followin and 40 refer to the The mass number chart: Isotope Isoto e symbol name atomic # mass # 19 37 17 35 # of rotons # of neutrons # of electrons Potassium-37 chlorine-35 uranium-235 238 uranium-238 92 235 92 238 5 10 12 26 boron-10 Magnesium-26 17 92 12 18 18 146 92 14 10 DIRECTIONS: For the following problems, show your work! (5 pts each) 3. Sulfur consists of four isotopes with masses of 32 (abundance 94.93%), 33 (abundance of 0.76%), (abundance of 4.29%), and 36 (abundance of 0.02%). Calculate the atomic mass of sulfur. (32 x 94.93) + (33 x 0.76) + (34 x 4.29) + (36 x 0.02) -------------------------------------------------------------100 = the atomic mass of sulfur is 32.09 (32.0942 rounded is 32.09) 3,037.76 + 25.08 + 145.86 + 0.72 ---------------------------------------100 3,209.42 ----------100 34 46 4. 47 common isotopes: nTi (8.0%), 22Ti (7.8%), æTi (73.4%), 49Ti (5.5%), 9}Ti (5.3%). What is the average atomic mass of titanium? Titanium has five 46 x .08 = 3.68 47 x .078 = 3.666 -> 3.67 48 x .734 = 35.232 -> 35.23 = 47.92 is the average atomic mass of titanium 49 x .055 = 2.695 -> 2.70 50 x .053 = 2.65 47.923 -> 47.92 5. Boron exists in two isotopes, boron-10 and boron-II. Based on the atomic mass, which isotope should be more abundant? n, The atomic mass of boron is 10.81 u. 10.81 u is much more closer to 11u compared to 10 u, therefore, there has to be more of boron-11. Solving for X: 11u - ux = 10.81u 0.19u = ux x = 0.19 1 - x = 0.81 (10u)(x) + (11u)(1 - x) ---------------------------- = 10.81 u 100% U is the unit for atomic mass X is the proportion of boron-10 out of the total boron abundance which is 100% Boron-11 is much more abundant. As a result, the abundance of boron-11 is 81%, roughly.