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Problem 14a1
In a series of experiments, a chemist prepared three different compounds that contain only iodine and fluorine and determined the mass of each element in each compound: Compound Mass of Iodine (g) Mass of Fluorine (g) 1 4.75 3.56 2 7.64 3.43 3 9.41 9.86 (a) Calculate the mass of fluorine per gram of iodine in Compound 1 and 2.
Problem 14b
In a series of experiments, a chemist prepared three different compounds that contain only iodine and fluorine and determined the mass of each element in each compound: Compound Mass of Iodine (g) Mass of Fluorine (g) 1 4.75 3.56 2 7.64 3.43 3 9.41 9.86 (b) How do the numbers in part (a) support the atomic theory?
- Discovering which of the three subatomic particles proved to be the most difficult—the proton, neutron, or electron? Why?
Problem 15
Problem 16a
An unknown particle is caused to move between two electrically charged plates, as illustrated in Figure 2.7. You hypothesize that the particle is a proton. (a) If your hypothesis is correct, would the particle be deflected in the same or opposite direction as the b rays?
Problem 16b
An unknown particle is caused to move between two electrically charged plates, as illustrated in Figure 2.7. You hypothesize that the particle is a proton. (b) Would it be deflected by a smaller or larger amount than the b rays?
- What fraction of the a particles in Rutherford's gold foil experiment are scattered at large angles? Assume the gold foil is two layers thick, as shown in Figure 2.9, and that the approximate diameters of a gold atom and its nucleus are 270 pm and 1.0 * 10–2 pm, respectively. Hint: Calculate the cross sectional area occupied by the nucleus as a fraction of that occupied by the atom. Assume that the gold nuclei in each layer are offset from each other.
Problem 17
Problem 18b
Millikan determined the charge on the electron by studying the static charges on oil drops falling in an electric field (Figure 2.5). A student carried out this experiment using several oil drops for her measurements and calculated the charges on the drops. She obtained the following data: Droplet Calculated Charge (C) A 1.60 * 10-19 B 3.15 * 10-19 C 4.81 * 10-19 D 6.31 * 10-19 (b) What conclusion can the student draw from these data regarding the charge of the electron?
Problem 18c
Millikan determined the charge on the electron by studying the static charges on oil drops falling in an electric field (Figure 2.5). A student carried out this experiment using several oil drops for her measurements and calculated the charges on the drops. She obtained the following data: Droplet Calculated Charge (C) A 1.60 * 10-19 B 3.15 * 10-19 C 4.81 * 10-19 D 6.31 * 10-19 (c) What value (and to how many significant figures) should she report for the electronic charge?
Problem 19c
The radius of an atom of tungsten (W) is about 2.10 Å. (c) If the atom is assumed to be a sphere, what is the volume in m3 of a single W atom?
Problem 20a1
The radius of an atom of copper (Cu) is about 140 pm. (a) Express this distance in angstroms 1A 2.
Problem 20b
The radius of an atom of copper (Cu) is about 140 pm. (b) How many Cu atoms would have to be placed side by side to span a distance of 5.0 mm?
Problem 20c
The radius of an atom of copper (Cu) is about 140 pm. (c) If you assume that the Cu atom is a sphere, what is the volume in cm3 of a single atom?
- Answer the following questions without referring to Table 2.1: (a) What are the main subatomic particles that make up the atom? (b) What is the relative charge (in multiples of the electronic charge) of each proton? (b) What is the relative charge (in multiples of the electronic charge) of each neutron? (b) What is the relative charge (in multiples of the electronic charge) of each electron? (c) Which of the particles is the most massive? (d) Which is the least massive?
Problem 21
Problem 22a
Determine whether each of the following statements is true or false. If false, correct the statement to make it true: (a) The nucleus has most of the mass and comprises most of the volume of an atom.
Problem 22b
Determine whether each of the following statements is true or false. If false, correct the statement to make it true: (b) Every atom of a given element has the same number of protons.
Problem 22c
Determine whether each of the following statements is true or false. If false, correct the statement to make it true: (c) The number of electrons in an atom equals the number of neutrons in the atom.
Problem 22d
Determine whether each of the following statements is true or false. If false, correct the statement to make it true: (d) The protons in the nucleus of the helium atom are held together by a force called the strong nuclear force.
Problem 23a
Consider an atom of 10B. (a) How many protons, neutrons, and electrons does this atom contain?
Problem 23b
Consider an atom of 10B. (b) What is the symbol of the atom obtained by adding one proton to 10B?
Problem 23c
Consider an atom of 10B. (c) What is the symbol of the atom obtained by adding one neutron to 10B?
Problem 23d
Consider an atom of 10B. (d) Are either of the atoms obtained in parts (b) and (c) isotopes of 10B? If so which one?
Problem 24a
Consider an atom of 63Cu. (a) How many protons, neutrons, and electrons does this atom contain?
Problem 24b
Consider an atom of 58Ni. (b) What is the symbol of the ion obtained by removing two electrons from 58Ni?
Problem 24c
Consider an atom of 63Cu. (c) What is the symbol for the isotope of 63Cu that possesses 36 neutrons?
Problem 25a
(a) Define atomic number and mass number.
Problem 25b
(b) Which of these can vary without changing the identity of the element?
Problem 26a
(a) Which two of the following are isotopes of the same element: 3116X, 3115X, 3216X?
Problem 26b
(b) What is the identity of the element whose isotopes you have selected?
Problem 27a,b,c
How many protons, neutrons, and electrons are in the following atoms? (a) 84Kr (b) 200Hg (c) 70Ga
Problem 27d
How many protons, neutrons, and electrons are in the following atoms? (d) 80Br