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Chapter 2: Problem 65

How many protons and neutrons are in the nucleus of each of the following atoms? In a neutral atom of each element, how many electrons are present? a. \(^{79} \mathrm{Br}\) b. \(^{81} \mathrm{Br}\) c. \(^{239} \mathrm{Pu}\) d. \(^{133} \mathrm{Cs}\) e. \(^{3} \mathrm{H}\) f. \(^{56} \mathrm{Fe}\)

Short Answer

Expert verified
a. \(^{79}\mathrm{Br}\): 35 protons, 44 neutrons, 35 electrons b. \(^{81}\mathrm{Br}\): 35 protons, 46 neutrons, 35 electrons c. \(^{239}\mathrm{Pu}\): 94 protons, 145 neutrons, 94 electrons d. \(^{133}\mathrm{Cs}\): 55 protons, 78 neutrons, 55 electrons e. \(^{3}\mathrm{H}\): 1 proton, 2 neutrons, 1 electron f. \(^{56}\mathrm{Fe}\): 26 protons, 30 neutrons, 26 electrons

Step by step solution

01

a. Isotope \(^{79} \mathrm{Br}\)

To determine the number of protons, find the atomic number of Bromine (Br) using the periodic table, which is 35. Hence, the neutral atom of Bromine has 35 electrons. To find the number of neutrons, we subtract the atomic number from the mass number: 79 - 35 = 44 neutrons.
02

b. Isotope \(^{81}\mathrm{Br}\)

The atomic number of Bromine (Br) is still 35, so there are 35 protons and 35 electrons in a neutral atom. To find the number of neutrons, we subtract the atomic number from the mass number: 81 - 35 = 46 neutrons.
03

c. Isotope \(^{239}\mathrm{Pu}\)

To determine the number of protons, find the atomic number of Plutonium (Pu) using the periodic table, which is 94. Hence, the neutral atom of Plutonium has 94 electrons. To find the number of neutrons, we subtract the atomic number from the mass number: 239 - 94 = 145 neutrons.
04

d. Isotope \(^{133}\mathrm{Cs}\)

To determine the number of protons, find the atomic number of Cesium (Cs) using the periodic table, which is 55. Hence, the neutral atom of Cesium has 55 electrons. To find the number of neutrons, we subtract the atomic number from the mass number: 133 - 55 = 78 neutrons.
05

e. Isotope \(^{3}\mathrm{H}\)

To determine the number of protons, find the atomic number of Hydrogen (H) using the periodic table, which is 1. Hence, the neutral atom of Hydrogen has 1 electron. To find the number of neutrons, we subtract the atomic number from the mass number: 3 - 1 = 2 neutrons.
06

f. Isotope \(^{56}\mathrm{Fe}\)

To determine the number of protons, find the atomic number of Iron (Fe) using the periodic table, which is 26. Hence, the neutral atom of Iron has 26 electrons. To find the number of neutrons, we subtract the atomic number from the mass number: 56 - 26 = 30 neutrons.

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Most popular questions from this chapter

Name the compounds in parts a–d and write the formulas for the compounds in parts e–h. a. \(\mathrm{Hg}_{2} \mathrm{O}\) b. \(\mathrm{FeBr}_{3}\) c. \(\mathrm{CoS}\) d. \(\mathrm{TiCl}_{4}\) e. tin(II) nitride f. cobalt(III) iodide g. mercury(II) oxide h. chromium(VI) sulfide

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