Fill in the gaps in the following table, assuming each column represents a neutral atom. Symbol 79 Br Protons 25 82 Neutrons 30 64 Electrons 48 86 Mass no. 222 207 Complete the fourth row of the table.

everyone in this example, we need to fill in the fourth row of our given table. So the fourth row is going to correspond to the section describing electrons. And in the first column of the fourth row, we notice we're given the F E three plus carry on and the mass number 58. So writing out that chemical symbol, we would have F E three plus. And recall that the mass number is always written in the left hand superscript of our chemical symbol. We want to recall that our mass number is found from taking our number of protons and adding it to our number of neutrons. And so we want to find our number of electrons. So we're going to focus on finding the number of protons first by considering a neutral atom of iron Where we find on our periodic tables. Iron in the transition middle section corresponding to atomic number 26. And we want to recall that the atomic number is always written in the left hand subscript of our chemical symbol for a given atom. And so we want to recall that the atomic number will correspond to our number of protons, which will equal our number of electrons in a neutral atom. But in this case we don't have a neutral atom. We have a three plus catalon, meaning that we will lose Three electrons. And so we want to recall that because we have 26 electrons in a neutral atom of iron based on our number of protons, in our atomic number For a charged atom of iron with a three plus charge. We would subtract three electrons leaving us with 23 electrons to fill in for our first column of our fourth row. So we have 23 electrons. And then for the third row of our fourth column we are given the number of protons, the number of neutrons and a net charge. So again, we want to find based on our number of protons we want to recall that corresponds to our atomic number. So we want to find atomic number 76 on the periodic table because we're given 76 protons and to find 76 on the periodic table, we would see that that corresponds to the atom osmium or Os. And so we want to recall again that the atomic number is written in the left hand subscript of our chemical symbol. And so to find our number of electrons, we want to recognize that we have a net charge of plus one on this atom. So we would fill that in on the right hand side and recall that the plus one charge means we lose one electron. And so assuming that in a neutral atom of osmium We would have 76 protons and 76 electrons For a charged atom of osmium with a plus one charge. We would take those 76 electrons and we would subtract one electron leaving us with 75 electrons. And so we would say that to fill in the third column of the 4th row. We would have 75 electrons as our answer here. And so to complete this example, we would have these two boxed in yellow, um, answers as our final answer. So I hope that everything we reviewed is clear. If you have any questions, please leave them down below, and I will see everyone in the next practice video.

Ch.2 - Atoms, Molecules, and Ions

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Brown 15th Edition

Ch.2 - Atoms, Molecules, and Ions

Problem 29d

Chapter 2, Problem 29d

Fill in the gaps in the following table, assuming each column represents a neutral atom.
Symbol ⁷⁹Br
Protons 25 82
Neutrons 30 64
Electrons 48 86
Mass no. 222 207

Complete the fourth row of the table.

Verified step by step guidance

insert step 1: Understand that the mass number of an atom is the sum of its protons and neutrons.

insert step 2: For the first column, calculate the number of protons in the atom with symbol ^79Br. Since the mass number is 79 and the number of neutrons is not given, use the periodic table to find that bromine (Br) has 35 protons.

insert step 3: For the second column, calculate the number of neutrons by subtracting the number of protons from the mass number: 222 - 25 = 197 neutrons.

insert step 4: For the third column, calculate the number of electrons. Since the atom is neutral, the number of electrons equals the number of protons, which is 82.

insert step 5: For the fourth row, calculate the number of protons by subtracting the number of neutrons from the mass number: 207 - 64 = 143 protons. Since the atom is neutral, the number of electrons is also 143.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Atomic Structure

Atoms consist of protons, neutrons, and electrons. Protons are positively charged particles found in the nucleus, while neutrons are neutral particles also located in the nucleus. Electrons are negatively charged and orbit the nucleus. The number of protons defines the element, while the total number of protons and neutrons gives the atomic mass.

Isotopes

Isotopes are variants of a particular chemical element that have the same number of protons but different numbers of neutrons. This results in different atomic masses for the isotopes. For example, bromine-79 (79Br) has 35 protons and 44 neutrons, while another isotope may have a different neutron count, affecting its stability and properties.

Mass Number

The mass number of an atom is the sum of its protons and neutrons. It is a whole number that represents the total mass of the nucleus. In the context of the table, filling in the mass number requires adding the number of protons and neutrons for each atom, which helps in identifying the specific isotope and its characteristics.