16) 17) ) 16) When two elements, A and B, form two different compounds, the masses of element that combine with 1 g of element A can be expressed as a ratio of small whole numbers. Which law does this refer to? A) Law of definite proportions B) Law of the conservation of mass C) Law of multiple proportions D) First law of thermodynamics E) Law of modern atomic theory 17) Identify the description of an atom. A) neutrons and electrons in nucleus, protons in orbitals B) neutrons in nucleus: protons and electrons in orbitals protons and electrons in nucleus, neutrons in orbitals D) electrons in nucleus; protons and neutrons in orbitals E) protons and neutrons in nucleus, electrons in orbitals 18) What are isotopes? A) Atoms with the same number of protons but different numbers of electrons. B) Atoms with the same number of neutrons but different numbers of electrons. C) Atoms with the same number of protons but different numbers of neutrons. D) Atoms with the same number of electrons but different numbers of protons. E) Atoms with the same number of neutrons but different numbers of protons. 19) The mass number is equal to A) the sum of the number of protons, neutrons, and electrons B) the sum of the number of protons and neutrons the sum of the number of the electrons and protons D) the sum of the number of the neutrons and electrons 18) 19) 20) What does "X" represent in the following symbol? 20) SO 35 E) chlorine A) bromine B) scandium C) selenium D) mercury 21) Determine the number of protons, neutrons, and electrons in the following: 40 21) ) 18 A) p* -40 B) pt = 22 C) pt = 18 D) pt =18 E) pt - 18 n=22 n = 18 n su n18 n = 22 e-18 e-18 40 e-22 e" =18 22) How many electrons are in arsenic? A) 41 B) 33 ) 22) C) 75 D) 42 E) 41.9