What distinguishes the mass spectrum of 2,2-dimethylpropane from the mass spectra of pentane and isopentane?

Mass spectrum is plot in which y-axis is taken as intensity and x-axis is taken as m/z also known as mass to charge ratio in order to analyse a compound.

The mass to charge ratio depends upon the molecular mass of a compound or the corresponding cation fragments while, the intensity mainly depends upon the stability and concentration (natural abundance) of atoms / ions respectively.

In said problem we can distinguish 2,2-dimethylpropane from Pentane and Isopentane by different ways using mass spectrum. As shown in attached picture all of the given compounds give a same m/z value of 57. As the carbocation formed by 2,2-dimethylpropane is tertiary so its intensity will be greater because this cation is more stable. Therefore, the peak m/z = 57 for Pentane (primary carbocation) and Isopentane (secondary carbocation) will be having less intensity than 2,2-dimethylpentane.

explanation:

metals have excess of electrons whereas non-metals have deficiency of electrons. thus, in order to gain stability metals easily donate their electrons to the non-metals.

for example, electronic configuration of sodium is and electronic configuration of phosphorous is .

when a phosphorous atom and sodium atom combine together then sodium will donate is extra one electron to the phosphorous atom. as a result there will be formation of ionic bond between sodium and phosphorous.

the reaction will be as follows.

there, are three sodium sodium atoms and each of them will donate its one extra electron to phosphorous atom. thus, the sub-shell of phosphorous gets completely filled.  

thus, we can conclude that electrons are transferred from atoms of sodium to atoms of phosphorous. this transfer makes the sodium atoms donate one electron and the phosphorous atoms to gain one electron. as a result, the sodium and phosphorus atoms strongly attract each other.

answer by yourhope:

how do models compare to real-world objects?

d. most models represent a real-world object in a simpler way.

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