The correct option is A,
Isotopes are atoms of an element, which have the same number of protons but different number of neutrons in the nucleus of the atom. Thus, isotopes have the same atomic number but different mass number.
Looking at the options given above, you will discover that Chlorine which is given in option A is correct. Both type of chlorine has the same atomic number, which is 17, but they have different atomic masses, the atomic mass of the first one is 35 while that of the second one is 37.<span />
Answer:
Mostly Para
Explanation:
First, let's assume that the molecule is the toluene (A benzene with a methyl group as radical).
Now the nitration reaction is a reaction in which the nitric acid in presence of sulfuric acid, react with the benzene molecule, to introduce the nitro group into the molecule. The nitro group is a relative strong deactiviting group and is metha director, so, further reactions that occur will be in the metha position.
Now, in this case, the methyl group is a weak activating group in the molecule of benzene, and is always ortho and para director for the simple fact that this molecule (The methyl group) is a donor of electrons instead of atracting group of electrons. Therefore for these two reasons, when the nitration occurs,it will go to the ortho or para position.
Now which position will prefer to go? it's true it can go either ortho or para, however, let's use the steric hindrance principle. Although the methyl group it's not a very voluminous and big molecule, it still exerts a little steric hindrance, and the nitro group would rather go to a position where no molecule is present so it can attach easily. It's like you have two doors that lead to the same place, but in one door you have a kid in the middle and the other door is free to go, you'll rather pass by the door which is free instead of the door with the kid in the middle even though you can pass for that door too. Same thing happens here. Therefore the correct option will be mostly para.
Isotopes are atoms of the same element that differ in the number of neutrons.
Remember that all the atoms of an element have the same number of protons. So the only difference between isotopes of an element is the number of neutrons.
86 Sr means that the mass number of this isotope is 86. Also, remember that the mass number is the number of protons plus the number of neutrons.
87 Sr means that the mass number of this isotope is 87.
So, 86 Sr and 87 Sr differ 1 neutron.
Answer: 1 neutron
