protactinium

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Related to Element 91: Element 94, Element 92, Element 93, Element 90, Element 89, Element 101

protactinium

 (Pa) [pro″tak-tin´e-um]
a chemical element, atomic number 91, atomic weight 231. (See Appendix 6.)

pro·tac·tin·i·um (Pa),

(prō'tak-tin'ē-ŭm),
A radioactive element, atomic no. 91, atomic wt. 231.03588, formed in the decay of uranium and thorium; its most long-lived isotope, 231Pa, has a half-life of 32,500 years.
[G. prōtos, first]

protactinium

/pro·tac·tin·i·um/ (Pa) (pro″tak-tin´e-um) chemical element, at. no. 91.

protactinium (Pa)

[-taktin′ē·əm]
Etymology: Gk, protos, first, aktis, ray
a radioactive element. Its atomic number is 91, and its atomic mass is 231.04. Its decay products are actinium and an alpha particle. See also actinium.

pro·tac·tin·i·um

(Pa) (prō'tak-tin'ē-ŭm)
A radioactive element, atomic no. 91, atomic wt. 231.03588, formed in the decay of uranium and thorium; its longest-lived isotope, 231Pa, has a half-life of 32,500 years.
[G. prōtos, first]

protactinium

a chemical element, atomic number 91, atomic weight 231, symbol Pa. See Table 6.
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