Answer:
The wavelength for the transition from n = 4 to n = 2 is<u> 486nm</u> and the name name given to the spectroscopic series belongs to <u>The Balmer series.</u>
Explanation
lets calculate -
Rydberg equation- 
where ,
is wavelength , R is Rydberg constant (
),
and
are the quantum numbers of the energy levels. (where
)
Now putting the given values in the equation,


Wavelength 
=
= 486nm
<u> Therefore , the wavelength is 486nm and it belongs to The Balmer series.</u>
Answer:
The correct option is: c. 15
Explanation:
Phosphorous is a chemical element which belongs to the group 15 of the periodic table and has atomic number 15. It is a highly reactive non-metal of the p-group.
Since, atomic number of an atom is the number of electrons and number of protons for neutral atoms.
So, the number of protons = number of electrons = 15
The atomic mass is obtained by adding the number of neutrons and the protons.
So, number of neutrons + number of protons = 30
So, number of neutrons + 15 = 30
Therefore, the number of neutrons in ³⁰P = 15
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