<u>Answer:</u> The longest wavelength of light is 656.5 nm
<u>Explanation:</u>
For the longest wavelength, the transition should be from n to n+1, where: n = lower energy level
To calculate the wavelength of light, we use Rydberg's Equation:

Where,
= Wavelength of radiation
= Rydberg's Constant = 
= Higher energy level = 
= Lower energy level = 2 (Balmer series)
Putting the values in above equation, we get:

Converting this into nanometers, we use the conversion factor:

So, 
Hence, the longest wavelength of light is 656.5 nm
Structure is in document below.
The mononitration of p-xylene can be easily carried out at 30 degrees C.
Para-xylene<span> (</span><span>p-xylene</span><span>) is an </span>aromatic hydrocarbon, <span>one of the three </span>isomers<span> of </span>dimethylbenzene. Para-xylene is colorless and highly flammable, not acutely toxic and has some <span>narcotic effects.</span>
I’m guessing the answer is AX (the first one) sorry if I am wrong tho
The last one. A bond of two or more of the same element.
Answer:
(4) All atoms of a given element must have the same atomic number
Explanation:
Atomic number : It is defined as the number of electrons or number of protons present in a neutral atom.
However, when we talk about the atomic number of the ion, it is not equal to the number of electrons as electron can be gained or loosed.
This is why, more appropriately, the number of the protons which are present in the nucleus of the atom is called the atomic number.
Mass number is the number of the entities present in the nucleus which is the equal to the sum of the number of protons and electrons.
Mass number = Number of protons + Number of neutrons
<u>Thus, atomic number of an element is an unique property of the element and it's atom.</u>