The answer is: when the aim is to show electron distributions in shells
An orbital notation is more appropriate if you want to show how the electrons of an atom are distributed in each subshell. This is because there are some atoms that have special electronic configurations that aren't obvious in just written configurations.
The balanced reaction for combustion is as follows ;
2C₂H₅OH + 6O₂ ---> 4CO₂ + 6H₂O
the stoichiometry of C₂H₅OH to O₂ is 2:6
that means 2 mol of C₂H₅OH reacts with 6 mol of O₂.
when 1 mol of C₂H₅OH reacts with 6/2 mol of O₂,
then 0.3020 mol of C₂H₅OH reacts with - 6/2 x 0.3020
therefore number of O₂ moles reacted = 0.91 mol
Answer:
2.15 mg of uranium-238 decays
Explanation:
For decay of radioactive nuclide-

where N is amount of radioactive nuclide after t time,
is initial amount of radioactive nuclide and
is half life of radioactive nuclide
Here
,
and 
So,
so, N = 2.446 mg
mass of uranium-238 decays = (4.60-2.446) mg = 2.15 mg
Answer: Lanthanide and actinide series
Explanation: The elements with partially or fully filled f orbitals belong to f block elements.
f block elements include lanthanides and actinides. They are called so the lanthanides contain the first element named as lanthanum and actinides contain first element named as actinium. They are also called as inner transition elements.
All of them have general electronic configuration:
, where n = 6-7