What's the next in the series?

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

Until it is measured, not known. Yet how you miss it when it has gone. What is it?

Replace the question mark with the number below given a simple math problem.

I have no doors but I have keys, I have no rooms but I have space, you can enter but you can’t leave! What am I?

On a windy rainy night , I was driving in my car.
When i reach the bus stand , i see three people waiting for the bus.

1. An old lady who needs an immediate medical attention
2. My Best Friend
3. Girl whom i love from childhood

My car is a two seat, so can you tell me , what i have done in this situation ?

_ _ _ IE _ _
_ _ _ IE _
_ _ IE _ _
_ _ IE _
_ _ _ _ IE

Like you see, some letters have gone missing from these words that contain the IE pair at some or the other place. The letters that will be used to fill the blanks are given below. Use them and form meaningful words. Can you do that?

A, C, D, F, H, K, L, M, N, N, O, R, R, S, S, S, T, T, Y and Y.

Eight of us go fourth, not back, to protect our king from an attack. What are we?

1 + 9 + 8 = ?
considering, 28 + 8 + 92 = 10

what does the below rebus means?

The pound is not a finish.

We are sharing a few instructions below, which you have to use in any suitable order to modify the above sentence such that the end sentence is a scientific fact.

- Eliminate a letter and supplement another in its place.
- Take away one word.
- Remove one letter from one word.
- Get rid of two letters from one word.
- Swap a word with its antonym.