What's the next in the series?

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

Our product and our sum always give the same answer. Who are we?

While house hunting in London, I came across a very good leasehold property Discussing the lease the landlady told me:

'The property was originally on a 99 years lease and two-thirds of the time passed is equal to four-fifths of the time to come. Now work it out for yourself and see how many years are to go!

When it is alive we sing, when it is dead we clap our hands. What is it?

You can see it everyday, But cannot touch it at will. What is it?

I start and end with 500 and carry a 5 in my heart. But I require the first letter and the first number to be complete. I am the name of a King.

Who am I ?

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

What is it?

Using Only Five 5's and any mathematical operator make sum as 37

I have four wings but can't fly.
I express no emotions.
I am found on the exact spot every time you look.
I keep toiling away with a little sound.

Do you know what am I?

Can you figure out the logic I used to decide the order of the following words:
gun, shoe, spree, door, hive, kicks, heaven, gate, line, den