What does below chemistry rebus means?

I never stop running even when I standstill. If I am formed by joining two identical bodies together, can you guess who I am?

What has 88 keys?

Replace the question mark with the correct number, given the pair of numbers exhibits a similar relationship?

? : 3839 :: 11 : 1209

Which alphabet letter is a question?

A four-digit number (not beginning with 0) can be represented by ABCD. There is one number such that ABCD=A^B*C^D, where A^B means A raised to the B power. Can you find it?

Can you name four days which start with the letter 'T'?

Through your logical capabilities, can you make 7 an even?

What number does the below three word/phrase identify and why?
1. Deck
2. Year
3. Singing in the Rain

There was a minor accident with a doctor's son but the doctor noticed no major injury. After the treatment, the father of that doctors son is sitting with the son of the doctor without the doctor being in the room.

How can this be possible?