Questions on Ionisation energies ( IE )?

1)The first ionization energies of a sequence of elements of increasing proton( atomic number) are given below :

548 , 620 , 660 , 660 , 680

explain , giving reasons why is this sequence of elements derived from the transition metals.

2)The order of the first ionisation energies of Radon( rn ), fracium ( fr) and radium (ra) have their order of their ionisation energies as follow starting from the least endothermic to most endothermic.

Ra , Fr , Rn

since Ra have higher nuclear charge given the more number of protons , im confused why it have lower IE compared to Rn, and since both Fr and Ra are in the S orbital , Ra which have higher nuclear charge should he harder to remove and in addition shielding effect is negiglible in this case.... but it was not what i assumed? can someone help me? or was the answer wrong? cause this was a mcq question..

Questions on Ionisation energies ( IE )?microsoft

2) Out of these 3 elements, Rn has the largest 1st IE. This is because it already has a stable configuration, and removing an electron will cause it to attain a -1 charge, which is very unlikely.

Ra has a larger 1st IE than Fr because it has a larger nuclear charge, and removing electron is more difficult. [Fr 380 kJ/mol; Ra 509 kJ/mol]

Since Rn has the largest 1st IE, this implies that it needs to take in more energy in order to free an electron =%26gt; most endothermic. Fr require the least energy =%26gt; least endothermic.

So i think the answer should be Fr, Ra, Rn. Do check with your teacher and let me know the answer =)