#the list of atoms
atoms=["Hydrogen","Helium","Lithium","Beryllium","Boron","Carbon","Nitrogen","Oxygen","Fluorine","Neon","Sodium","Magnesium","Aluminum","Silicon","Phosphorus","Sulfur","Chlorine","Argon","Potassium","Calcium","Scandium","Titanium","Vanadium","Chromium","Manganese","Iron","Cobalt","Nickel","Copper","Zinc","Gallium","Germanium","Arsenic","Selenium","Bromine","Krypton","Rubidium","Strontium","Yttrium","Zirconium","Niobium","Molybdenum","Technetium","Ruthenium","Rhodium","Palladium","Silver","Cadmium","Indium","Tin","Antimony","Tellurium","Iodine","Xenon","Cesium","Barium","Lanthanum","Cerium","Praseodymium","Neodymium","Promethium","Samarium","Europium","Gadolinium","Terbium","Dysprosium","Holmium","Erbium","Thulium","Ytterbium","Lutetium","Hafnium","Tantalum","Tungsten","Rhenium","Osmium","Iridium","Platinum","Gold","Mercury","Thallium","Lead","Bismuth","Polonium","Astatine","Radon","Francium","Radium"]
choice=""
while choice!="x":
    print("%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%")
    print("A T O M   F I N D E R")
    print("*****************************************")
    print("/n")
    print("a:Append an atom to the list")
    print("b:Remove an atom from the list")
    print("c:print the list")
    print("d:sort the list")
    print("e:the length of the list")
    print("f:edit an atom ")
    print("x:exit the program")
    print("/n")
    choice=input("choose an option:")
   
    if choice=="a":
       name=input("enter the name of an atom to add:")
       atoms.append(name)
       print(name,"has been added to the list")
       
    if choice=="b":
      nmae=input("enter the name of an atom to remove")
      atoms.remove(name)
      print(name,"has been removed to the list")
      
    if choice=="c":
      print(atoms)
      
    if choice=="d":
        atoms.sort()
        print(atoms)

    if choice=="e":
        print(len(atoms))
       
    if choice=="f":
        print(atoms)
        i=int(input("which atom do you want to change?"))

the link of my program 
https://www.onlinegdb.com/edit/VOwLBvgaYV