How to extract some specific values from json - ruby-on-rails

Question

I am still trying to create an app where the user could transform his name or a word with chemical elements (like breaking bad logo).
The user will enter a word in a text field and when he'll submit it will return him the word with the corresponding chemical symbols if they match, or it will display the "raw" letters if they don't match.
ex: If no symbol matches I am keepking the initial entry so it could be: hello => He ll O (bold char represent the existing chemical symbols)
I know this could be done in js, but the challenge is ROR (btw I don't know any js...)
In an earlier question I had just a hash like:
symbols =
{"cr" => "Cr",
"sb" => "Sb",
"ag" => "Ag",
"ar" => "Ar",
"as" => "As",
"at" => "At",
"n" => "N",
"ba" => "Ba",
"bk" => "Bk"}
and I was using name.downcase.gsub!(Regexp.union(symbols.keys), symbols)to transform the user entry. Actually I need more datas... that's why I chosen the json file.
Like on this picture i will need to use:
"number"
"small"
"molar"
(and the "name" will appear in a caption below)
I have organized a .json file with all the symbols I may need in the app and stored it in my config/periodic_table.json (pasted just a sample cause it's very long).
1°) If a user enter "hello" how do I loop to search for the "he" hash and print the "name","number", "small" and the "molar"
2°) I will use the json as a database (I will use heroku to deploy) so do I have anything to transform for using json and pg together?
[ "symbols"
{
"h": {
"name": "Hydrogen",
"number": 1,
"small": "H",
"molar": 1.00794
},
"he": {
"name": "Helium",
"number": 2,
"small": "He",
"molar": 4.002602
},
"b": {
"name": "Boron",
"number": 5,
"small": "B",
"molar": 10.811
},
"c": {
"name": "Carbon",
"number": 6,
"small": "C",
"molar": 12.0107
},
"n": {
"name": "Nitrogen",
"number": 7,
"small": "N",
"molar": 14.0067
}
}
]
I will need to loop first with the symbols that contain 3 chars, then 2 then 1... shall i change anythin in the json, like an harray for the hashes that contains 3 chars, another for 2 chars , and for 1char?

Answer 1

Correct Json Format
[{
"symbols":{
"h":{
"name": "Hydrogen",
"number": 1,
"small": "H",
"molar": 1.0079
},
"he":{
"name": "Helium",
"number": 2,
"small": "He",
"molar": 4.002602
},
"b": {
"name": "Boron",
"number": 5,
"small": "B",
"molar": 10.811
},
"c": {
"name": "Carbon",
"number": 6,
"small": "C",
"molar": 12.0107
},
"n": {
"name": "Nitrogen",
"number": 7,
"small": "N",
"molar": 14.0067
}
}
}]