What's the next in the series?

H, Be, F, S, Mn, Kr, In, Gd, Tl, ?

If 2 workers can complete painting 2 walls in exactly 2 hours.

How many workers would be needed to paint 18 walls in 6 hours?

I make a loud sound when I’m changing. When I do change, I get bigger but weigh less. What am I?

I hide my treasure in the ground, my tail is big and fluffy. If you spot me in a tree, please don’t call me scruffy. What am I?

A man is found unconscious in front of a store at two in the morning. His head is bleeding and there’s a brick laying next to him. When the police arrive, they carry the man to jail. Why did they arrest him?

If you drop a 15 kg iron bar and a 5 kg bag of cotton from a height of 50 meters which will reach the ground first?

Henry has been caught stealing cattle and is brought into town for justice. The judge is his ex-wife Gretchen, who wants to show him some sympathy, but the law calls for two shots to be taken at Henry from close range. To make things a little better for Henry, Gretchen tells him she will place two bullets into a six-chambered revolver in successive order. She will spin the chamber, close it, and take one shot. If Henry is still alive, she will then either take another shot, or spin the chamber again before shooting.

Henry is a bit incredulous that his ex-wife would carry out the punishment, and a bit sad that she was always such a rule follower. He steels himself as Gretchen loads the chambers, spins the revolver, and pulls the trigger. Whew! It was blank. Then Gretchen asks, 'Do you want me to pull the trigger again, or should I spin the chamber a second time before pulling the trigger?'

What should Henry choose?

By including only four matchsticks in below picture, you have to make "Four Triangles And Two Squares"

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

which number am I?

Can you spot what's wrong with the following sentence?

PETER WAS ANGRY AT
HIMSELF BECAUSE HE
ACCIDENTALLY LEFT THE
THE KEYS TO HIS CAR
AT HIS FRIEND'S HOUSE.