A laboratory rat is exposed to an alpha-radiation source whose activity is 14.3 mCi. (a) What is the activity of the radiation in disintegrations per second? In becquerels?
Ch.21 - Nuclear Chemistry
Chapter 21, Problem 71a
The table to the right gives the number of protons (p) and neutrons (n) for four isotopes. (a) Write the symbol for each of the isotopes.

1
Identify the element by its number of protons. The atomic number, which is the number of protons, determines the element. For example, if an isotope has 6 protons, it corresponds to Carbon (C).
Determine the mass number of each isotope. The mass number is the sum of the number of protons and neutrons in the nucleus. For instance, if an isotope has 6 protons and 8 neutrons, its mass number is 14.
Write the symbol for each isotope using the format: \\( ^{mass\ number}_{atomic\ number}Element \\). For the example above with Carbon, the symbol would be \\( ^{14}_6C \\).
Repeat the process for each isotope listed in the table, ensuring to use the correct atomic number and mass number for each.
Review the symbols to ensure they correctly represent the isotopes as per the data given in the table regarding the number of protons and neutrons.

Verified video answer for a similar problem:
This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
2mWas this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Isotopes
Isotopes are variants of a particular chemical element that have the same number of protons but different numbers of neutrons. This difference in neutron count results in varying atomic masses for the isotopes of the same element. For example, carbon-12 and carbon-14 are isotopes of carbon, with 6 protons and 6 or 8 neutrons, respectively.
Recommended video:
Guided course
Isotopes
Nuclear Symbol Notation
Nuclear symbol notation is a way to represent isotopes using the element's symbol along with its mass number and atomic number. The mass number (total number of protons and neutrons) is written as a superscript to the left of the element symbol, while the atomic number (number of protons) is written as a subscript. For instance, the notation for carbon-14 is written as ¹⁴₆C.
Recommended video:
Guided course
Standard Notation to Scientific Notation
Atomic Structure
Atomic structure refers to the arrangement of protons, neutrons, and electrons within an atom. Protons and neutrons reside in the nucleus, while electrons orbit around the nucleus in electron shells. Understanding atomic structure is essential for identifying isotopes, as it helps clarify how variations in neutron numbers affect the overall properties of the element.
Recommended video:
Guided course
Atom Structure
Related Practice
Textbook Question
511
views
Textbook Question
A laboratory rat is exposed to an alpha-radiation source whose activity is 14.3 mCi. (b) The rat has a mass of 385 g and is exposed to the radiation for 14.0 s, absorbing 35% of the emitted alpha particles, each having an energy of 9.12 * 10-13 J. Calculate the absorbed dose in millirads and grays.
99
views
Textbook Question
Radon-222 decays to a stable nucleus by a series of three alpha emissions and two beta emissions. What is the stable nucleus that is formed?
1435
views
Textbook Question
Chlorine has two stable nuclides, 35Cl and 37Cl. In contrast, 36Cl is a radioactive nuclide that decays by beta emission. (a) What is the product of decay of 36Cl?
462
views