What does below chemistry rebus means?

It's a protector.
It sits on a bridge.
One individual can see directly through it, while others wonder what it hides.

What is it?

I am the fastest animal but cannot climb the tree. What am I?

How can you leave a room with two legs and return with six legs?

I am a prime number.
The double of myself is equal to the square of me.

which number am I?

Consider this about a word: The first two letters signify a male, the first three letters signify a female, the first four letters signify a great, while the entire world signifies a great woman. What is the word?

It has a long neck, A name of a bird, Feeds on cargo of ships, It's not alive,

What is it?

Jigsaw captured 100 people and make them stand in a circle and all these people are labelled as Person1, Person2, Person3... Person100. He made them play a crazy game in which Person 1 shot Person 2 and pass the gun to the next person and so on until one stands alive.

Which person will survive in the end?

What seven-letter word has hundreds of letters in it?

A new Engineering building containing 100 offices had just been completed. John was hired to paint the numbers 1 to 100 on the doors. How many times will John have to paint the number nine (9)?