Answer: They are arranged by atomic number.
What are the elements so i can help?????
chlorine has the atomic mass of 35.5 and is a non metal in the halogen family
a compound in chemistry, is any substance that is formed when two or more chemical elements are chemically bonded together. A prime example of this is H20. You are combining hydrogen to oxygen, giving you a compund element. I hope this helps you. :)
Answer :
(a) The energy of blue light (in eV) is 2.77 eV
(b) The wavelength of blue light is 
Explanation:
The relation between the energy and frequency is:

where,
h = Plank's constant = 
Given :
Frequency = 
Conversion used :

So,


Also,

So,


The energy of blue light (in eV) is 2.77 eV
The relation between frequency and wavelength is shown below as:

Where,
c = the speed of light = 
Frequency = 
So, Wavelength is:


Conversion used : 
The wavelength of blue light is 