7. What is the Roman numeral that should be used in the following: silver (_______) sulfide?A. IB. No Roman numeral should be used here.C. IID. III8. Why is pure silicon a poor conductor at room temperature?A. It is a metal.B. Its valence electrons are held tightly within a crystal structure.C. Its valence electrons are held loosely by a positive nucleus.D. It is a nonmetal.9. What is the specific name of the covalent compound consisting of nine carbon atoms and 20 hydrogen atoms?A. NonaneB. Nonacarbon decahydroxideC. Nonahydrogen decacarbonD. Hydrocarbon10. Atoms of the group 15 elements tend to react to form _______ ions.A. 52B. 3+C. 32D. 5+11. In the periodic table the period number indicatesA. the reactivity levels for elements in that period.B. the number of dots shown on the Lewis dot diagrams for elements in that period.C. the number of valence electrons for elements in that period.D. the number of the outermost energy level for elements in that period.14. These two elements are most likely good conductors of heat and electricity and shiny when solid.A. B and IB. P and SeC. Au and BrD. Sn and Ag15. Which pairing below does not correctly match the scientist with the contribution to the understanding of the atom?A. Dalton and the initial proposal of the atomic theory of matterB. Rutherford and the understanding that the atom has a small dense nucleus with a positive chargeC. Proust and the realization that the elements of compounds are found in certain proportions by massD. Thomson and the law of definite proportions16. A potassium atom can achieve a stable octet byA. gaining one electron.B. sharing one electron.C. losing seven electrons.D. losing one electron.