
Concept explainers
The following radioactive isotopes are used in medicine for things such as imaging organs, studying blood circulation, and treating cancer. Give the number of neutrons present in each isotope: 198Au, 47Ca, 60Co, 18F, 125I, 131I, 42K, 43K, 24Na, 32P, 85Sr, 99Tc.

Interpretation:
The total number of neutrons present in the given set of radioactive isotopes needs to be given.
Concept introduction:
The total number of protons in an atom is said to be its atomic number. By using the total number of protons and neutrons all the atoms can be identified. Atomic number is denoted by “Z”. Atomic number is a characteristic of each and every atom in an element.
The total number of neutrons and protons of an atom is said to be its mass number. By using the total number of protons and neutrons all the atoms can be identified. Mass number is denoted by “A”.
Atomic number does not change for atoms present in an element while mass number can change due to difference in number of neutrons. These are known as isotopes.
Total number of neutrons present in an atom can be found out of finding the difference between mass number and atomic number.
To Determine: The number of neutrons present in the given radioactive isotopes.
Answer to Problem 2.22QP
The number of neutrons in
The number of neutrons in
The number of neutrons in
The number of neutrons in
The number of neutrons in
The number of neutrons in
The number of neutrons in
The number of neutrons in
The number of neutrons in
The number of neutrons in
The number of neutrons in
The number of neutrons in
Explanation of Solution
To determine the number of neutrons present in
Atom of the element given= gold
Mass number (A)= 198
Total number of protons (Z)=79
The number of neutrons in any atom can be got by finding the difference between mass number and total number of protons.
Therefore, the mass number of
To determine the number of neutrons present in
Atom of the element given= calcium
Mass number (A)= 47
Total number of protons (Z)=20
The number of neutrons in any atom can be got by finding the difference between mass number and total number of protons.
Therefore, the mass number of
To determine the number of neutrons present in
Atom of the element given= cobalt
Mass number (A)= 60
Total number of protons (Z)=27
The number of neutrons in any atom can be got by finding the difference between mass number and total number of protons.
Therefore, the mass number of
To determine the number of neutrons present in
Atom of the element given= fluorine
Mass number (A)= 18
Total number of protons (Z)=9
The number of neutrons in any atom can be got by finding the difference between mass number and total number of protons.
Therefore, the mass number of
To determine the number of neutrons present in
Atom of the element given= iodine
Mass number (A)= 125
Total number of protons (Z)=53
The number of neutrons in any atom can be got by finding the difference between mass number and total number of protons.
Therefore, the mass number of
To determine the number of neutrons present in
Atom of the element given= iodine
Mass number (A)= 131
Total number of protons (Z)=53
The number of neutrons in any atom can be got by finding the difference between mass number and total number of protons.
Therefore, the mass number of
To determine the number of neutrons present in
Atom of the element given= potassium
Mass number (A)= 42
Total number of protons (Z)=19
The number of neutrons in any atom can be got by finding the difference between mass number and total number of protons.
Therefore, the mass number of
To determine the number of neutrons present in
Atom of the element given= potassium
Mass number (A)= 43
Total number of protons (Z)=19
The number of neutrons in any atom can be got by finding the difference between mass number and total number of protons.
Therefore, the mass number of
To determine the number of neutrons present in
Atom of the element given= sodium
Mass number (A)= 24
Total number of protons (Z)=11
The number of neutrons in any atom can be got by finding the difference between mass number and total number of protons.
Therefore, the mass number of
To determine the number of neutrons present in
Atom of the element given= phosphorous
Mass number (A)= 32
Total number of protons (Z)=15
The number of neutrons in any atom can be got by finding the difference between mass number and total number of protons.
Therefore, the mass number of
To determine the number of neutrons present in
Atom of the element given= strontium
Mass number (A)= 85
Total number of protons (Z)=38
The number of neutrons in any atom can be got by finding the difference between mass number and total number of protons.
Therefore, the mass number of
To determine the number of neutrons present in
Atom of the element given= technitium
Mass number (A)= 99
Total number of protons (Z)=43
The number of neutrons in any atom can be got by finding the difference between mass number and total number of protons.
Therefore, the mass number of
The number of neutrons in the given set of radioisotopes was determined.
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Chapter 2 Solutions
Chemistry: Atoms First
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