In[]:=
UnitConvert[ElementData["Hydrogen","IonizationEnergies"](Quantity[1,"Moles"]/Quantity[1,"AvogadroNumber"]),"ElectronVolts"]
Out[]=

13.598
eV

In[]:=
EntityClass["AtomicLevel",{"Hydrogen",1}][EntityProperty["AtomicLevel","Wavenumber"]]
Out[]=

0.×
-2
10
/cm
,
82258.9
/cm
,
82259.0
/cm
,
82259.2
/cm
,
82259.3
/cm
,
97492.2
/cm
,
97492.2
/cm
,
97492.3
/cm
,
97492.3
/cm
,
97492.3
/cm
,
97492.4
/cm
,
102823.8
/cm
,
102823.9
/cm
,
102823.9
/cm
,
102823.9
/cm
,
102823.9
/cm
,
102823.9
/cm
,
102823.9
/cm
,
102823.9
/cm
,
105291.6
/cm
,
105291.6
/cm
,
105291.7
/cm
,
105291.7
/cm
,
105291.7
/cm
,
105291.7
/cm
,
105291.7
/cm
,
105291.7
/cm
,
105291.7
/cm
,
105291.7
/cm
,
106632.1
/cm
,
106632.1
/cm
,
106632.2
/cm
,
106632.2
/cm
,
106632.2
/cm
,
106632.2
/cm
,
106632.2
/cm
,
106632.2
/cm
,
106632.2
/cm
,
106632.2
/cm
,
106632.2
/cm
,
106632.2
/cm
,
107440.4
/cm
,
107440.4
/cm
,
107440.4
/cm
,
107440.4
/cm
,
107440.4
/cm
,
107440.5
/cm
,
107965.0
/cm
,
107965.0
/cm
,
107965.1
/cm
,
107965.1
/cm
,
107965.1
/cm
,
107965.1
/cm
,
108324.7
/cm
,
108324.7
/cm
,
108324.7
/cm
,
108324.7
/cm
,
108324.7
/cm
,
108324.7
/cm
,
108582.0
/cm
,
108582.0
/cm
,
108582.0
/cm
,
108582.0
/cm
,
108582.0
/cm
,
108582.0
/cm
,
108772.3
/cm
,
108772.3
/cm
,
108772.3
/cm
,
108772.3
/cm
,
108772.3
/cm
,
108772.3
/cm
,
108917.1
/cm
,
108917.1
/cm
,
108917.1
/cm
,
108917.1
/cm
,
108917.1
/cm
,
108917.1
/cm
,
109029.8
/cm
,
109119.2
/cm
,
109191.3
/cm
,
109250.3
/cm
,
109299.3
/cm
,
109340.3
/cm
,
109375.0
/cm
,
109404.6
/cm
,
109430.1
/cm
,
109452.2
/cm
,
109471.4
/cm
,
109488.4
/cm
,
109503.3
/cm
,
109516.5
/cm
,
109528.3
/cm
,
109538.9
/cm
,
109548.4
/cm
,
109556.9
/cm
,
109564.6
/cm
,
109571.7
/cm
,
109578.1
/cm
,
109583.9
/cm
,
109589.2
/cm
,
109594.1
/cm
,
109598.7
/cm
,
109602.8
/cm
,
109606.7
/cm
,
109610.2
/cm
,
109678.8
/cm
