Question

Without looking at data in the text, sketch a qualitative graph of the third ionization energy versus atomic number for the elements Na through Ar, and explain your graph.

Short answer

Answer:

Step-by-step solution

Explain IE using concepts of valence electrons and extra stability of half and fully filled orbital:

Na has one valence electron only. So removal of 3 electrons requires a very large amount of energy.

In the case of Mg, the third IE is forthe first core electron. So it also needs a very high energy.

Al has 3 electrons and these valence electrons are being removed. So, the third IE of Al is very low.

Now IEincreases in moving left to right in a period. So third IE of Si, as well as S and Cl, gradually increases.

P has a completely filled outer configuration leading to slightly lower IE.

Ar attainshalf-filled configuration by losing 3 electrons. So its third IE is also low.