Pa	Z =  91	◊ ◊ ◊ ◊ ◊	Protactinium
			From the Greek "protos + aktis", meaning "first beam element"
(AM) Atomic Mass	231.0359  amu	♦	Oxidation States	+4, +5
(BP) Boiling Point	n/a	♦	(MP) Melting Point	1600  °C
(ρ) Density	n/a	♦	Crystal Structure	Tetragonal
( χ ) Electronegativity	1.5	♦	(AR) Atomic Radius	n/a
Physical State	Solid	♦	(C) Heat Capacity	n/a
Electronic-Config	[Rn]  5f2  6d1  7s2	♦	(I1) First Ionization E	568.3  kJ/mol
(ΔHvap) Heat of Vaporization	481  kJ/mol	♦	(ΔHfus) Heat of Fusion	12.34  kJ/mol
Year of Discovery	1913	♦	Location of Discovery	United Kingdom
(E°) Standard Potential	Pa4+⇔ Pa3+ (-1.900 V)
Stable isotopes	None. All natural isotopes are radioactive
Discovered/Synthesized by	Kasimir Fajans, O.H. Göhring
Natural Source	Isolated from the decay of Uranium
Common Uses	Scientific study
Other Info	One of the rarest and most expensive naturally occurring elements
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