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It is important that O-Level Chemistry students understand the concepts about Isotopes in order to answer application questions related to it.
Isotopes are atoms of the same element with the same number of protons but different number of neutrons.
This mean that for isotopes, the number of protons and electrons will be the same but the mass (nucleon) number will be different.
Take chlorine as an example. 75% of naturally chlorine atoms are Cl-35 and the remaining being Cl-37. By simple math, you should get the average atomic mass (Ar) of chlorine to be 35.5 as shown in most Periodic Table.
Click HERE for more in-depth discussions on Isotopes in the topic of Atomic Structure.
Most elements in the periodic table have isotopes, and many of these isotopes are radioactive. Some of the common uses of radioactive isotopes are in medical & chemical industry. Clean energy industry such as the Nuclear Plants are making use of the radioactive isotopes to produce large amount of energy in several countries, much to the disapproval by groups that are aware of the danger in radioactive substance.
Let’s take a look at a very common exam-based Multiple Choice Question (MCQ).
Quick Check 1:
Isotopes are
A) atoms of the same element with different masses
B) atoms of different elements with different masses
C) atoms of different elements with the same mass
D) atoms of the same element with same mass
Based on our discussion, we should arrived at answer A with two sets of keywords “atoms of the same element” and “different masses”.
Now, try out the following MCQ question on your own:
Quick Check 2:
Which of the following statements concerning the two isotopes 146C and 147N is/are correct?
1. Both isotopes have the same chemical properties
2. Both isotopes contain 14 nucleons per atom
3. The carbon isotope has more neutrons per atom than the nitrogen isotope
A) 1, 2 and 3 are correct
B) 1 and 2 only are correct
C) 2 and 3 only are correct
D) 3 only is correct
Go try it out and leave your thoughts/answers in the comment section below. Do participate in the discussions to help each other to master Chemistry.
PS: If you find this post on Isotopes useful to any of your friends, feel free to forward to them. =) Keep sharing!
ISOTOPES
Answer B
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hey dis is really very helpfull for the o levelz students…!!thanx for loading them…!!!now today mah concepts for Isotopes are now clear..!! thank yew..!!
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Only 2 and 3 are correct
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This is very good 4 all student…Thanks 4 loadind them,I appreciate.
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b) 1 & 2 .are correct
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1 and 2 are corect
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the ans is B
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Thanx
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I see here that majority of the answers are B. However I do not comprehend why 1 is correct and 3 is incorrect, help please?
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1 is not correct because chemical properties of an element depends on its number of electron which is the same as its proton(?tomic) number of a neutral element . comparing the nitrogen and carbon atoms it both have different atomic numbers.
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1st option is wrong. The chemical properties of the element depends on the valence electrons of the atom. Carbon has 4 valence electrons and nitrogen has 5 valence electrons.
2n option is correct. The 14 refers to the nucleon (proton + neutron) no of the isotope.
3rd option is correct. Carbon isotope has 8 (14-6) neutrons, which is more than Nitrogen isotope (14-7=7 neutron).
Answer is Option C, 2 and 3 are correct.
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witney ramsey Reply:
March 7th, 2012 at 9:43 am
hey the chemical properties depend on number of electrons and proton to have the same number but not number of valence that why the chemical properties of atom is not the same with is ion bcoz the number of electron in ion is differ from proton .so it means that the chemical properties of isotopes are the same
coz have the same number of proton and electron
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the answer is c means 1and2 are correctly this is the way i think
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the anwer is b means 1 and 2 this is the way i think
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