What's the next in the series?

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

I have one of the three numbers: 1, 2, or 3 in my mind. I speak only truth. You can ask me just one question for which I will only reply in yes or no or don't know. What question will you ask from me so that you are able to know the number?

Once while in his court, King Akbar asked Birbal to write something on a wall that makes one sad when read in good times and makes one happy when read in sad times.

He took only a few moment and wrote something that fit the requirements. What did he write?

The answer I give is yes, but what I mean is no. What was the question?

How many triangles can you find in this given picture?

When I go in I might cause pain. I cause you to spit and ask you not to swallow. I can fill your hole. What am I?

using four eights (8) and a one (1) and one mathematical symbol , create the number 100

Can you solve this picture maths equation?

In the given figure, move three matchsticks so that the resulting figure contains two rectangles.

I am quite hot but become too cold if you remove the first two letters. What am I?