Isotopes and Their Importance
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ISOTOPES AND THEIR IMPORTANCE 1. Elements that exhibit isotopy have more than one isotope. (a) Definite isotope. ____________________________________________________________________ _ (b) Give two examples of elements that exhibit isotopy. ____________________________________________________________________ _ 2. Bromine-79 and bromine-81 are isotopes. (a) State two similarities of bromine-79 and bromine-81. (i) ___________________________________________________________________ (ii)________________________________________________________________ ___
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Transcript of Isotopes and Their Importance
ISOTOPES AND THEIR IMPORTANCE
1. Elements that exhibit isotopy have more than one isotope. (a) Definite isotope.
_____________________________________________________________________
(b) Give two examples of elements that exhibit isotopy. _____________________________________________________________________
2. Bromine-79 and bromine-81 are isotopes.
(a) State two similarities of bromine-79 and bromine-81. (i) ___________________________________________________________________
(ii)___________________________________________________________________
(b) State two differences between bromine-79 and bromine-81. (i)___________________________________________________________________
(ii)__________________________________________________________________
3. Isotopes are very useful in many sectors. Usually, radioisotopes are involved.
(a) What is a radioisotope? ___ _________________________________________________________________
(b) State the uses of the following radioisotopes :
(i) Carbon-14. __________________________________________________________
(ii) Sodium-24. _________________________________________________________
(iii) Cobalt-60. __________________________________________________________
(iv) Phosphorus -32. _____________________________________________________
(v) Uranium-235. _______________________________________________________
.
4. Iodine-127 and iodine-131 are two isotopes of iodine. Table 2 below shows the number of each subatomic particles in an atom of iodine-127.
Proton Neutron Electron
number 53 74 53
TABLE 2
(a) Suggest a reason why one of the isotopes of iodine is called iodine-127? _________________________________________________________________
(b) Tabulate the number of subatomic particles found in an iodine-131 atom in a table similar to Table 2.
(c) (i) Which isotope of iodine is used in the field of medicine to determine the health of human thyroid gland?
________________________________________________________________
(ii) Suggest a reason for your choice in c(i).
_______________________________________________________________
(d) “Isotopes of an element have the same physical and chemical properties.” The above statement is found in a student’s notebook and it is incorrect. Correct the sentence and rewrite it below.
_______________________________________________________________
(e) The relative atomic mass of chlorine is 35.5. Suggest a reason to explain why the relative atomic mass of chlorine is not a whole number or integer?
______________________________________________________________
______________________________________________________________
ISOTOPES AND THEIR IMPORTANCE
ANSWERS
1. Elements that exhibit isotopy have more than one isotope. (a) Definite isotope. Answer: Atoms of the same element with same proton number but different nucleon number.
(b) Give two examples of elements that exhibit isotopy. Answer:
Carbon, chlorine, oxygen, bromine, hydrogen
2. Bromine-79 and bromine-81 are isotopes.
(a) State two similarities of bromine-79 and bromine-81. Answer:
(i) Same proton number
(ii) Same chemical properties
(b) State two differences between bromine-79 and bromine-81. Answer: (i) Different nucleon number
(ii) Different chemical properties
3. Isotopes are very useful in many sectors. Usually, radioisotopes are involved.
(a) What is a radioisotope? Answer:
Unstable isotopes that will decompose spontaneously by emitting radioactive raysto become more stable isotopes.
(b) State the uses of the following radioisotopes : (i) Carbon-14.
Answer:
To determine the age of fossils. (ii) Sodium-24.
Answer: To determine the underground water pipe leakage.
(iii) Cobalt-60.
Answer:
To produce gamma rays to kill cancer cells.
(iv) Phosphorus -32. Answer:
To study the metabolism of phosphorus by plants. (v) Uranium-235.
Answer: As fuel in nuclear power stations.
4. Iodine-127 and iodine-131 are two isotopes of iodine. Table 2 below shows the number of each subatomic particles in an atom of iodine-127.
Proton Neutron Electron
number 53 74 53
TABLE 2
(a) Suggest a reason why one of the isotopes of iodine is called iodine-127? Answer: Iodine-127 has a nucleon number of 127 which consists of 53 protons and 74 neutrons.
(b) Tabulate the number of subatomic particles found in an iodine-131 atom in a table similar to Table 2.
Answer:
Proton Neutron Electronnumber 53 78 53
(c) (i) Which isotope of iodine is used in the field of medicine to determine the health of human thyroid gland? Answer: Iodine-131
(ii) Suggest a reason for your choice in c(i). Answer: Iodine-131 is radioactive and gives off radiations.
(d) “Isotopes of an element have the same physical and chemical properties.” The above statement is found in a student’s notebook and it is incorrect. Correct the sentence and rewrite it below. Answer: Isotopes of an element have the same chemical properties but different physical properties.
(e) The relative atomic mass of chlorine is 35.5. Suggest a reason to explain why the relative atomic mass of chlorine is not a whole number or integer?
Answer:
Chlorine has two isotopes of which 75% of chlorine exists as chlorine-35 and
25% of chlorine exists as chlorine-37.
