Li-6 and Li-7, which one has the greater abundance ? the atomic weight of lithium is 6.941?

Question

Pls give some explaination

Answer 1

6.941 is an AVERAGE of weights. So if it's an AVERAGE the atomic weight GIVEN is CLOSER to 7 than 6. So, the answer would be Li-7.

Answer 2

There must be far more Li 7 than Li 6 if the atomic weight is much closer to 7 than it is to 6

Wikipedia says:

6Li 7.5% is stable with 3 neutrons
7Li 92.5% is stable with 4 neutrons

6Li content may be as low as 3.75% in
natural samples. 7Li would therefore
have a content of up to 96.25%.

Table of all Lithium isotopes:
isotope protons neutrons isotopic mass

Li-3 3 0 3.03078
Li-4 3 1 4.02719
Li-5 3 2 5.01254
Li-6 3 3 6.015122795
Li-7 3 4 7.01600455
Li-8 3 5 8.02248736
Li-9 3 6 9.0267895
Li-10 3 7 10.035481
Li-11 3 8 11.043798
Li-12 3 9 12.05378

Answer 3

Li-7

Answer 4

An abundance ratio of 12.14±0.4 was obtained for Li7/Li6. On the basis of this ratio the masses of the two isotopes are 7.016±0.002 and 6.016±0.002 and the packing fractions are 23±3 and 26±3, respectively

Answer 5

relative atomic weight is given by

(a *weightA+b * weightB+ ... +z * weightZ)/(a+b+...+z)
where a, b, ...,z are the mole fractions of the isotopes A,B,...,Z
a+b+...+z=1
6.941=(a * 6+b * 7)/1
a+b=1
a=1-b
6.941=(1-b)*6+b*7
6.941=6-6b+7b
.941=b
a=1-b
a=0.059
so there is 94.1% Li7 and 5.9 *Li6 assuming no other isotopes