Year is 2050. Aliens have been discovered and is now acknowledged as a friendly species towards humans. They now comes for regular visits on Earth and has a friendly relation towards humans. One day, a UFO was on a regular patrol toward Venus but suddenly it suffered a failure and crashed on Earth. Inside there are 7 aliens. All look tensed and worried but they knew the humans would help them. So, they started discussing who is going to bring the repairing kit from the humans. Following is the conversation:
A1: I am skinny. I am so skinny that I might blow away as soon as I step outside. Somebody, please go. I can't.
A2: I can't even sustain on Earth's environment. There is no way I am going.
A3: Hey, chill. I have been here once. I came to know that I am quite famous here. I should go.
A4(To A3): Look, I understand your sentiment but I should be the one to go. I am the one who is most sustainable to Earth's environment. Humans like me. I am going.
A5: What about me?! I am quite bright and cheerful. I am also quite helpful to them. I should go.
A6: My body release toxic fumes and rays. Uhh, I don't know, I might even kill someone. I am not going
A7: Ehhh, just go, anyone go, enough of this argument. I am fat and obese. I can't listen to your arguments. I am staying inside the chamber. Please go, we are getting late.
Main question: What are the names of the aliens?
Side question: Who should be the one to go?(Only one can go)
They should be panicking by now but they are calm, like really calm. Why are they so calm? How are they so calm?
Something related to chemistry (klabuster_'s answer is partially correct)