Answer:
The answer is "3.81041978"
Explanation:
In 1860 
Answer:
According to Bohr, the amount of energy needed to move an electron from one zone to another is a fixed, finite amount. ... The electron with its extra packet of energy becomes excited, and promptly moves out of its lower energy level and takes up a position in a higher energy level. This situation is unstable, however.
Answer:
7. 3–ethyl–6 –methyldecane
8. 5–ethyl–2,2–dimethyl–4–propyl–4 –heptene
Explanation:
It is important to note that when naming organic compounds having two or more different substituent groups, we simply name them alphabetically.
The name of the compound given in the question above can be written as follow:
7. Obtaining the name of the compound.
Compound contains:
I. Decane.
II. 3–ethyl.
III. 6 –methyl.
Naming alphabetically, we have
3–ethyl–6 –methyldecane
8. Obtaining the name of the compound.
Compound contains:
I. 2,2–dimethyl.
II. 4–propyl.
III. 4 –heptene.
IV. 5–ethyl.
Naming alphabetically, we have
5–ethyl–2,2–dimethyl–4–propyl–4 –heptene
Answer:- The natural abundance of 
is 0.478 or 47.8% and 
is 0.522 or 52.2% .
Solution:- Average atomic mass of an element is calculated from the atomic masses of it's isotopes and their abundances using the formula:
Average atomic mass = mass of first isotope(abundance) + mass of second isotope(abundance)
We have been given with atomic masses for and as 150.919860 and 152.921243 amu, respectively. Average atomic mass of Eu is 151.964 amu.
Sum of natural abundances of isotopes of an element is always 1. If we assume the abundance of as n then the abundance of would be 1-n .
Let's plug in the values in the formula:
151.964=150.919860n+152.921243-152.921243n
on keeping similar terms on same side:
negative sign is on both sides so it is canceled:
The abundance of is 0.478 which is 47.8%.
The abundance of is = 
= 0.522 which is 52.2%
Hence, the natural abundance of is 0.478 or 47.8% and is 0.522 or 52.2% .
