Neon I think. Go to the periodic table and see which one is the 11th
Event 1 is an example of a chemical reaction.
<u>Explanation:</u>
Whenever if two solutions are mixed, then if there is any color change, or evolution of any vapors, bubbles or gas formation or if there is any formation of a color or white precipitate confirms that the occurrence of a chemical reaction.
If nothing happens said above then it is said that there is no chemical reaction occurs.
Here in the event 1 a clear liquid in one beaker poured into clear liquid in beaker 2 then there is a formation of orange liquid, which means there is a formation of a new colored liquid confirms that the chemical reaction occurred.
Answer:
the wavelength of radiation emitted is 
Explanation:
The energy of the Bohr's hydrogen atom can be expressed with the formula:

For n = 7:


For n = 4


The electron goes from the n = 7 to the n = 4, then :


Wavelength of the radiation emitted:

where;
hc = 1242 eV.nm


Reichsteins substance if I remember correctly.
Hope this helped! :)
- Juju