Isotopes

[BodybldgDoc]

Isotopes have
A. the same number of protons and electrons.
B. the same atomic number and equal number of protons
C. the same mass number and equal numbers of protons
D. the same atomic number and equal numbers of neutrons
E. the same mass number and equal numbers of neutrons.

It says the answer is B. However isnt A true? I thought Isotopes of an element always have the same number of protons and electrons but the number of neutrons may differ.
Also doesnt the statement "the same atomic number and equal number of protons" not make sense? thoughts?

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[CyborgNinjaX]

Isotopes have
A. the same number of protons and electrons.
B. the same atomic number and equal number of protons
C. the same mass number and equal numbers of protons
D. the same atomic number and equal numbers of neutrons
E. the same mass number and equal numbers of neutrons.

It says the answer is B. However isnt A true? I thought Isotopes of an element always have the same number of protons and electrons but the number of neutrons may differ.
Also doesnt the statement "the same atomic number and equal number of protons" not make sense? thoughts?

A and B both seem right to me... B is just a case of redundancy. The atomic number is the number of protons. Where did you get this from?

 

[jdmsamurai]

i dont think an isotope needs to have the same number of electrons. just the same number of protons (atomic number, which defines the chemical, think of decay, etc..etc..), but different in the number of neutrons.

 

[jdmsamurai]

A and B both seem right to me... B is just a case of redundancy. The atomic number is the number of protons. Where did you get this from?

what if you didnt know the atomic number is the number of protons?

 

[BodybldgDoc]

A and B both seem right to me... B is just a case of redundancy. The atomic number is the number of protons. Where did you get this from?

yeah B is redundant. Its basically stating the same thing twice. The number of protons and electrons have to be the same.
btw i got this from the barrons book. I know people have said the book is full of errors but since i had the book i figured i'd run through the practice tests in it. thanks for the responses guys

 

[CyborgNinjaX]

So this is what a bad question looks like from Barron's...