Another gas that was used to fill balloons was hydrogen. The reason why hydrogen is not used today is because it use to cause many fires when it was used to fill balloons up.
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Answer: Hydrogen and Helium
Explanation: Hydrogen is made from from one proton and one electron, making them one of the simplest forms of elements in the universe. Combining hydrogen atoms creates helium, the second most common element in the Universe.
Answer:
A
Explanation:
The purpose of the periodic table was to organize elements as they were discovered into periods and groups, according to their properties. It was not just a naming of elements, as a list.
Answer:
I believe the answer is A: *It is the simplest form of matter" not 100% sure but I think that's correct
Explanation:
