Problem 66
Complete each of the statements a through d using 1,2, or \(3:\) 1\. decreases 2\. increases 3\. remains the same Going from left to right across Period 4 , a. the ionization energy b. the atomic size c. the metallic character d. the number of valence electrons
Problem 69
According to Dalton's atomic theory, which of the following are true? a. Atoms of an element are identical to atoms of other elements. b. Every element is made of atoms. c. Atoms of two different elements combine to form compounds. d. In a chemical reaction, some atoms disappear and new atoms appear.
Problem 70
Use Rutherford's gold-foil experiment to answer each of the following: a. What did Rutherford expect to happen when he aimed particles at the gold foil? b. How did the results differ from what he expected? c. How did he use the results to propose a model of the atom?
Problem 74
Cadmium, atomic number 48 , consists of eight naturally occurring isotopes. Do you expect any of the isotopes to have the atomic mass listed on the periodic table for cadmium? Explain.
Problem 76
Complete the following table for the three naturally occurring isotopes of silicon, the major component in computer chips: $$ \begin{array}{|l|c|c|c|} \hline & \multicolumn{3}{|c|} {\text { Isotope }} \\ \hline & { }^{28} \mathrm{Si} & { }_{14}^{29} \mathrm{Si} & { }_{14}^{30} \mathrm{Si} \\ \hline \text { Number of protons } & & & \\ \hline \text { Number of neutrons } & & & \\ \hline \text { Number of electrons } & & & \\ \hline \text { Atomic number } & & & \\ \hline \text { Mass number } & & & \\ \hline \end{array} $$
Problem 81
Of the elements \(\mathrm{Na}, \mathrm{Mg}, \mathrm{Si}, \mathrm{S}, \mathrm{Cl}\), and \(\mathrm{Ar}\), identify one that fits each of the following: a. largest atomic size b. a halogen c. electron arrangement \(2,8,4\) d. highest ionization energy e. in Group \(6 \mathrm{~A}(16)\) f. most metallic character g. two valence electrons
Problem 82
Of the elements \(\mathrm{Sn}, \mathrm{Xe}, \mathrm{Te}, \mathrm{Sr}, \mathrm{I}\), and \(\mathrm{Rb}\), identify one that fits each of the following: a. smallest atomic size b. an alkaline earth metal c. a metalloid d. lowest ionization energy e. in Group \(4 \mathrm{~A}(14)\) f. least metallic character g. seven valence electrons
Problem 83
Give the group number and period number for each of the following clements: a. bromine b. argon c. potassium d. radium
Problem 84
Give the group number and period number for each of the following elements: a. radon b. arsenic c. carbon d. neon
Problem 85
Indicate if each of the following statements is true or false: a. The proton is a negatively charged particle. b. The neutron is 2000 times as heavy as a proton. c. The atomic mass unit is based on a carbon atom with 6 protons and 6 neutrons. d. The nucleus is the largest part of the atom. e. The electrons are located outside the nucleus.
