as your question is incomplete i predicted your question tell me if question is wrong i will ready to help you anytime
the question i predicted is
Three isotopes of an element have mass numbers m,m+1 and m+2.If the mean mass number is ( m +0.5) then which of the following ratios may be accepted for m,(m+1) and (m+2) in that order
The mass number is the total number of protons and neutrons in the atom. But this is more of a maths question rather than chemistry.
Let's assume there are x units of the isotope with mass number m
y units of the isotope with mass number m+1
z units of the isotope with mass number m+2
So the mean would be (xm + y(m+1) + z(m+2)) / (x+y+z) [Mean = Total sum/Total quantity]
which is equal to m+0.5 [Given in question]
Solving this we get, 0.5(x - y - 3z) = 0=> x = y+3z equation (1)
Now we can put values of y and z and get x. There can be infinitely many values of x, y and z.
Here amongst the options, we can see that option (b) matches this criterion.
To be precise, if we take a constant k, then x=4k, y=k and c=k satisfy equation (1).
We can also see that option (a) and option (c) don't satisfy equation (1)
So amongst the options, option (b) is the answer.
As a check, if we take other ratios which satisfy equation (1) they can also be an answer to the question.
e.g. 7:1:2 => x=7k, y=k, z=2k
Now the mean would be, (xm + y(m+1) + z(m+2))/(x+y+z)
Putting the values,
(7km + k(m+1) + 2k(m+2))/(7k + k + 2k)
= (10 km + 5k)/(10k)
= m + 0.5
So 7:1:2 can also be a ratio which satisfies the given criterion.
HOPE IT WAS HELPFUL
UPDATE ME IF QUESTION AND ANSWER WAS WRONG
-Isotopes are atoms of same element having the same atomic number but different mass number.
lsotopes of hydrogen
All atoms of the same element have the same number of protons, but some may have different numbers of neutrons. Different isotopes of an element generally have the same physical and chemical properties. That's because they have the same numbers of protons and electrons.
1 the same atomic number and same atomic mass number
isotopes of element have the same atomic number and different atomic mass number
it's option 2
hope it is helpful
element having equal number of protons but different neutrons
isotopes of an element is different in Neutron number.
Isotopes of different elements have different atomic masses
no its not necessary