QUESTION 11 In 1908, Ernst Rutherford won the Noble Prize in Chemistry for discovery that an atom has nucleus. that radon is a noble gas. that an atom can be "split" when bombarded with an alpha particle. that one element can change into another in chemical reaction.

Copper atoms. (a) What is the average mass of one copper atom? (b) Students in a college computer science class once sued the college because they were asked to calculate the cost of one atom and could not do it. But you are in a chemistry course, and you can do this. (See E. Felsenthal, Wall Street Journal, May 9, 1995.) If the cost of 2.0-mm diameter copper wire (99.9995% pure] is currently 41.70 for 7.0 g, what is the cost of one copper atom?

In 1886 Eugene Goldstein observed positively charged particles moving in the opposite direction to electrons in a cathode ray tube (illustrated below). From their mass, he concluded that these particles were formed from residual gas in the tube. For example, if the cathode ray tube contained helium, the canal rays consisted of He+ ions. Describe a process that could lead to these ions. Canal rays. In 1886, Eugene Goldstein detected a stream of particles traveling in the direction opposite to that of the negatively charged cathode rays (electrons). He called this stream of positive particles "canal rays:"

2.19 Naturally occurring uranium consists of two isotopes, whose masses and abundances are shown below: Only 235U can be used as fuel in a nuclear reactor, so uramium for use in the nuclear industry must be enriched in this isotope. If a sample of enriched uranium has an atomic weight of 235.684 amu, what percentage of 235LT is present?

Though the common isotope of aluminum has a mass number of 27, isotopes of aluminum have been isolated (or prepared in nuclear reactors) with mass numbers of 24, 25, 26, 28, 29, and 30. How many neutrons are present in each of these isotopes? Why are they all considered aluminum atoms, even though they differ greatly in mass? Write the atomic symbol for each isotope.

Match these by placing the correct notation in the appropriate blank. 3467Se3367As3567Br3672Kr a. Contains 33 neutrons b. Contains greatest number of neutrons c. Contains equal number of protons and neutrons d. Contains the same number of neutrons as there are protons in As-67

Fill in the following table:

Here are three fictitious elements and a molecular view of the atoms that compose them. The molar mass of the middle element, (b), is 25 grams per dozen (g/doz). (The atoms of these fictitious elements are much larger than ordinary atoms.) Based on the size of the atoms, do you expect the atomic masses of elements (a) and (c) to be greater than or less than (b)? How many atoms are present in 175 g of element (b)?

You perform a chemical reaction using the hypothetical elements A and B. These elements are represented by their molecular models shown below: The product of the reaction represented by molecular models is a Using the molecular models and the boxes, present a balanced chemical equation for the reaction of elements A and B. b Using the symbols A and B2 for the chemical reaction, write a balanced chemical equation. c What are some real-element possibilities for element B?