Periodic Table

I have 20 neutrons.

I contain 7 protons.

I am an actinide.

I am the lightest metal on the periodic table.

How many neutrons does manganese - 55?

I am the only liquid metal on the periodic table.

I am the only gas left of the zigzag line on the periodic table.

How many electrons does Aluminum - 27 have?

I am a halogen.

I have 47 protons.

My symbol is Au.

My average atomic mass is 19.00.

This group is made up of unreactive nonmetals.

This group is made up of very reactive nonmetals.

My symbol is Sn.

I am the heaviest noble gas.

I have 12 protons.

I am the lightest element on the periodic table.

My symbol is H.

I am the lightest noble gas.