"You really shouldn't be getting this close to me, I wouldn't want to be responsible for you dying or something..."

It's quite common for poloniums to be smokers as a reference to the fact that polonium can be found in tobacco due to radioactive contaminates in their fertilisers, and Petronela used to smoke as well, but then she developed asthma and had to stop. Now she just chews gum all the time.

"Polonium solutions are first coloured in pink by the Po2+ ions, but then rapidly become yellow because alpha radiation from polonium ionizes the solvent and converts Po2+ into Po4+", yet despite this girlish exterior Petronela is quite stoic and exudes an air of wanting to left alone - literally. No, seriously, leave her alone because "a one-gram sample of 210Po will spontaneously heat up to above 500 °C", so a personification of it would dangerous to be next to, even without considering the radiation as everything near to them would get ridiculously hot, so a ton of precautions have to be taken to stop her from burning everything around her, including having her apartment crammed full of air conditioners and having her clothes specially designed to soak up as much of the heat as possible.

Luckily for the other elements, they're better able to withstand the heat, and with the precautions in place they're able to interact with her for extended periods of time without over heating. As such, and despite her stoicness, she's friends with quite a few elements, one of which being Thales, not just because they both have Peek-a-bangs or are both stoic, but because it was initially thought that thallium was what Alexander Litvinenko had been poisoned by.