If hydrogen was gone there would be no life. The sun is created with 75% hydrogen so the sun would be gone. The sun warms earths atmosphere so we would freeze after a few days.
Some uses of hydrogen
~In metal refiners
~Created in rocket fuel
~It's a nuclear fusion
If polonium was gone there wouldn't be space probes. They are used to make stuff in them. We wouldn't know about most of space because we couldn't explore it.
Uses of polonium
~Eliminates static electricity
~Is an Atomic heat source for 138.4 days
~It's in brushes to control radioactive emissions on TV
Dynamic Periodic Table. N.p., n.d. Web. 8 Dec. 2014. <http://www.ptable.com>.
Periodic Table of Elements and Chemistry. N.p., n.d. Web. 8 Dec. 2014. <http://www.chemicool.com>.
The Photographic Periodic Table of the Elements. N.p., n.d. Web. 8 Dec. 2014. <http://periodictableworld.com>.