The emission spectrum of a chemical element or chemical compound is the spectrum of frequencies of electromagnetic radiation emitted due to an atom or molecule making a transition from a high energy state to a lower energy state. The photon energy of the emitted photon is equal to the energy difference between the two states. There are many possible electron transitions for each atom, and each transition has a specific energy difference. This collection of different transitions, leading to different radiated wavelengths, make up an emission spectrum. Each element's emission spectrum is unique. Therefore, spectroscopy can be used to identify elements in matter of unknown composition. Similarly, the emission spectra of molecules can be used in chemical analysis of substances.
Calculate the activation energy for vacancy formation in Al given that the equilibrium number of vacancies at a temperature of 7
Answer:
Due to the resonance structures
Explanation:
In the question:
"<em>Explain why, when the guanidino group of arginine is protonated, the double-bonded nitrogen is the nitrogen that accepts the proton. There is a scheme of a reversible reaction, where one equivalent of the reactant reacts with two equivalents of H plus</em>"
We have to take into account the structure of the <u>amino acid</u> arginine. In which, we have the amino and the carboxylic groups in the right and the <u>guanidine group in the left</u>.
In this group, we have a central carbon with three nitrogen atoms around and a double bond with the nitrogen on the top. This nitrogen on the top will accept the proton because the structure produced will have a positive charge on this nitrogen. Then, the double bond with the carbon can be delocalized into the nitrogen producing a positive charge in the carbon.
In this structure (<u>the carbocation</u>), we can have several resonance structures. In the <em>blue option</em>, we can produce a double bond with the nitrogen on the right. In the <em>purple option</em>, we can produce a double bond with the nitrogen on the left.
In conclusion, if the nitrogen in the top on the guanidine group accepts an hydrogen atom and we will have <u>several resonance structures that can stabilize the molecule.</u> Due to this, the nitrogen in the top its the best option to accept hydrogens.
See figure 1
I hope it helps!
