2. Chemistry

Isotopes

What is an Isotope?

Isotopes | Matter | Physics | FuseSchool

 No. The atomic number is equal to the number of protons; therefore, the number of protons must be 6. 

 No. This would result in an atomic mass of 12 rather than 14. 

 No. This would result in an atom with a negative charge. The eight negatively charged electrons and six positively charged protons would result in a net charge of &ndash;2 for the atom. 

Consider that this carbon atom is uncharged.

A particular carbon isotope has an atomic number of 6 and an atomic mass of 14. The respective numbers of neutrons, protons, and electrons that this carbon isotope has are __________.

They have the same number of neutrons in their nuclei.

They behave differently in biological reactions. 

What is TRUE about carbon-13 and carbon-14?a) They are isotopes.b) They have the same mass number.c) They have the same number of neutrons in their nuclei.d) They behave differently in biological reactions.e) None of the above are true.

How Radioactive Isotopes Track Biological Molecules

Radioactive Isotopes

 Because they are not readily incorporated into biological reactions 

 No. Radioactive isotopes are used interchangeably with the stable isotope in living organisms. 

 Because they are difficult to detect in small amounts but living cells cannot distinguish them from the corresponding stable isotopes 

 No. Although living cells cannot distinguish radioactive isotopes from stable isotopes, radioactive isotopes are easy to detect in small amounts. 

 Because they decay spontaneously and give off energy and subatomic particles 

 No. This answer describes radioactive decay, but it does not explain the usefulness of radioactive isotopes in scientific research. 

 Because they can be used as tracers to follow particular atoms and molecules through metabolic pathways 

How could radioactive isotopes be put to work in research?

Why are radioactive isotopes useful in scientific research?

Incredible Isotopes

How are Carbon-13 and Nitrogen-15 respectively different from the more abundant isotopes Carbon-12 and Nitrogen-14? &nbsp;Carbon-13 and Nitrogen-15 _______________:a) Each have an extra neutron. &nbsp; &nbsp;&nbsp;b) Each have an extra proton. &nbsp; &nbsp;&nbsp;c) Each have one less neutron.d) Each have one less proton. &nbsp; &nbsp; &nbsp;e) Each have one less electron. &nbsp;

Dating fossilized material of once living things.

Radiation treatment to slow or stop the development of cancer cells.

Labeling regions of the body with radioactivity for special imaging techniques. 

Radioactive isotopes are utilized for all of the following except:a) Dating fossilized material of once living things.b) Radiation treatment to slow or stop the development of cancer cells.c) Labeling regions of the body with radioactivity for special imaging techniques.d) All of the above.

The atomic number of nitrogen is 7. Nitrogen-15 has a greater mass number than nitrogen-14 because the atomic nucleus of nitrogen-15 contains ________.a) 7 neutrons.b) 8 neutrons.c) 8 protons.d) 15 protons.

 An atom with 21 protons, 20 neutrons, and 21 electrons 

 No. The number of protons must stay the same for the element to remain calcium. 

 An atom with 20 protons, 20 neutrons, and 18 electrons 

 No. A change in the number of electrons would create an ion of calcium. 

 An atom with 21 protons, 21 neutrons, and 21 electrons 

 An atom with 20 protons, 21 neutrons, and 20 electrons 

Consider how isotopes of the same element vary.

The most common form of calcium has 20 protons, 20 neutrons, and 20 electrons. Which of the following elements would be an isotope of calcium?

 No. Atomic number refers to the number of protons in an atom. All isotopes of an element must have the same atomic number&mdash;hence the same number of protons. 

 No. The number of electrons determines whether the atoms of an element are ions. 

 No. All isotopes of an element must have the same atomic number&mdash;hence the same number of protons. 

Consider the meaning of iso-.

In which of the following will isotopes of an element always differ?

What are Isotopes? | Chemistry Basics

 No. The radioactive isotope has the lower atomic mass. 

 No. All isotopes of a given element have the same atomic number&mdash;hence the same number of protons. 

 No. All isotopes of a given element must have the same atomic number&mdash;hence the same number of protons. 

Consider how isotopes of an element differ.

Phosphorus-32 (radioactive) has __________ than phosphorus-35 (normal).

The isotope Carbon-14 has a half-life of 5,730 years. How many years must pass for a sample of Carbon-14 to break down to ¼ of its original amount?a) 5,730 years&nbsp;b) 17,190c) 11,460d) 2,865

We can represent atoms by listing the number of protons, neutrons, and electrons—for example, 2p+,2n0,2e− for helium. Which of the following represents the 18O isotope of oxygen?
a. 7p+,2n0,9e−
b. 8p+,10n0,8e−
c. 9p+,9n0,9e−
d. 10p+,8n0,9e-

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1. Introduction to Biology

3. Water

4. Biomolecules

5. Cell Components

6. The Membrane

7. Energy and Metabolism

8. Respiration

9. Photosynthesis

10. Cell Signaling

11. Cell Division

12. Meiosis

13. Mendelian Genetics

14. DNA Synthesis

15. Gene Expression

16. Regulation of Expression

17. Viruses

18. Biotechnology

19. Genomics

20. Development

21. Evolution by Natural Selection

22. Evolution of Populations

23. Speciation

24. History of Life on Earth

25. Phylogeny

26. Prokaryotes

27. Protists

28. Plants

29. Fungi

30. Overview of Animals

31. Invertebrates

32. Vertebrates