title: Isotopes of mendelevium
Isotopes of nihonium
Isotopes of plutonium
Isotopes of livermorium
Isotopes of darmstadtium
Isotopes of americium
Isotopes of meitnerium
Americium-241
Isotopes of roentgenium
Isotopes of vanadium
sentences: Mendelevium (Md) is a synthetic element, and thus a standard atomic weight cannot be given.
 Like all artificial elements, it has no stable isotopes.
 The first isotope to be synthesized was Md (which was also the first isotope of any element produced one atom at a time) in 1955.
 There are 16 known radioisotopes, ranging in atomic mass from Md to Md, and 5 isomers.
 The longest-lived isotope is Md with a half-life of 51.3 days, and the longest-lived isomer is Md with a half-life of 58.0 minutes.
Nihonium (Nh) is a synthetic element.
 Being synthetic, a standard atomic weight cannot be given and like all artificial elements, it has no stable isotopes.
 The first isotope to be synthesized was Nh as a decay product of Mc in 2003.
 The first isotope to be directly synthesized was Nh in 2004.
 There are 6 known radioisotopes from Nh to Nh, along with the unconfirmed Nh.
 The longest-lived isotope is Nh with a half-life of 19.6 seconds.
Plutonium (Pu) is an artificial element, except for trace quantities resulting from neutron capture by uranium, and thus a standard atomic weight cannot be given.
 Like all artificial elements, it has no stable isotopes.
 It was synthesized long before being found in nature, the first isotope synthesized being Pu in 1940.
 Twenty plutonium radioisotopes have been characterized.
 The most stable are Pu-244, with a half-life of 80.8 million years, Pu-242, with a half-life of 373,300 years, and Pu-239, with a half-life of 24,110 years.
 All of the remaining radioactive isotopes have half-lives that are less than 7,000 years.
 This element also has eight meta states, though none are very stable; all meta states have half-lives of less than one second.
Livermorium (Lv) is an artificial element, and thus a standard atomic weight cannot be given.
 Like all artificial elements, it has no stable isotopes.
 The first isotope to be synthesized was Lv in 2000.
 There are four known radioisotopes from Lv to Lv, as well as a few suggestive indications of a possible heavier isotope Lv.
 The longest-lived of the four well-characterised isotopes is Lv with a half-life of 53 ms.
Darmstadtium (Ds) is a synthetic element, and thus a standard atomic weight cannot be given.
 Like all synthetic elements, it has no stable isotopes.
 The first isotope to be synthesized was Ds in 1994.
 There are 9 known radioisotopes from Ds to Ds (with many gaps) and 2 or 3 known isomers.
 The longest-lived isotope is Ds with a half-life of 9.6 seconds.
Americium (Am) is an artificial element, and thus a standard atomic weight cannot be given.
 Like all artificial elements, it has no known stable isotopes.
 The first isotope to be synthesized was Am in 1944.
 The artificial element decays into alpha particles.
 Americium has an atomic number of 95 (the number of protons in the nucleus of the americium atom).
Meitnerium (Mt) is a synthetic element, and thus a standard atomic weight cannot be given.
 Like all synthetic elements, it has no stable isotopes.
 The first isotope to be synthesized was Mt in 1982, and this is also the only isotope directly synthesized; all other isotopes are only known as decay products of heavier elements.
 There are eight known isotopes, from Mt to Mt. There may also be two isomers.
 The longest-lived of the known isotopes is Mt with a half-life of 8 seconds.
 The unconfirmed heavier Mt appears to have an even longer half-life of 67 seconds.
Americium-241 (Am) is an isotope of americium.
 Like all isotopes of americium, it is radioactive.
 Am is the most common isotope of americium.
 It is the most prevalent isotope of americium in nuclear waste.
 Americium-241 has a half-life of 432.2 years.
 It is commonly found in ionization type smoke detectors.
 It is a potential fuel for long-lifetime radioisotope thermoelectric generators (RTGs).
 Its common parent nuclides are β from Pu, EC from Cm and α from Bk.
 Am is fissile and the critical mass of a bare sphere is 57.6-75.6 kilograms and a sphere diameter of 19–21 centimeters.
 Americium-241 has a specific activity of 3.43 Ci/g (curies per gram or 117.29 gigabequerels (GBq) per gram).
 It is commonly found in the form of americium-241 dioxide (AmO).
 This isotope also has one meta state; Am, with an exitation energy of 2.2 MeV, and a half-life of 1.23 μs.
 Its presence in plutonium is determined by the original concentration of plutonium-241 and the sample age.
 Because of the low penetration of alpha radiation, americium-241 only poses a health risk when ingested or inhaled.
 Older samples of plutonium containing plutonium-241 contain a buildup of Am.
 A chemical removal of americium-241 from reworked plutonium (e.g. during reworking of plutonium pits) may be required in some cases.
Roentgenium (Rg) is a synthetic element, and thus a standard atomic weight cannot be given.
 Like all synthetic elements, it has no stable isotopes.
 The first isotope to be synthesized was Rg in 1994, which is also the only directly synthesized isotope, all others are decay products of nihonium, moscovium, and tennessine.
 There are 7 known radioisotopes from Rg to Rg.
 The longest-lived isotope is Rg with a half-life of 2.1 minutes, although the unconfirmed Rg may have a longer half-life of about 11 minutes.
Naturally occurring vanadium (V) is composed of one stable isotope V and one radioactive isotope V with a half-life of 1.5×10 years.
 24 artificial radioisotopes have been characterized (in the range of mass number between 40 and 65) with the most stable being V with a half-life of 330 days, and V with a half-life of 15.9735 days.
 All of the remaining radioactive isotopes have half-lives shorter than an hour, the majority of them below 10 seconds, the least stable being V with a half-life shorter than 55 nanoseconds, with all of the isotopes lighter than it, and none of the heavier, have unknown half-lives.
 In 4 isotopes, metastable excited states were found (including 2 metastable states for V), which adds up to 5 meta states.

Question: Question: How many meta states does the first isotope to be synthesized in Am in 1944 have? 

 Your answer will be verified with exact match score. To ensure correct verification, only provide the answer within the <answer> </answer> tags. Do not put any sentences or reasoning process within the <answer> </answer> tags. 

Supporting Information: Paragraph 0 

 Mendelevium (Md) is a synthetic element, and thus a standard atomic weight cannot be given.
 Like all artificial elements, it has no stable isotopes.
 The first isotope to be synthesized was Md (which was also the first isotope of any element produced one atom at a time) in 1955.
 There are 16 known radioisotopes, ranging in atomic mass from Md to Md, and 5 isomers.
 The longest-lived isotope is Md with a half-life of 51.3 days, and the longest-lived isomer is Md with a half-life of 58.0 minutes. 

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Paragraph 1 

 Nihonium (Nh) is a synthetic element.
 Being synthetic, a standard atomic weight cannot be given and like all artificial elements, it has no stable isotopes.
 The first isotope to be synthesized was Nh as a decay product of Mc in 2003.
 The first isotope to be directly synthesized was Nh in 2004.
 There are 6 known radioisotopes from Nh to Nh, along with the unconfirmed Nh.
 The longest-lived isotope is Nh with a half-life of 19.6 seconds. 

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Paragraph 2 

 Plutonium (Pu) is an artificial element, except for trace quantities resulting from neutron capture by uranium, and thus a standard atomic weight cannot be given.
 Like all artificial elements, it has no stable isotopes.
 It was synthesized long before being found in nature, the first isotope synthesized being Pu in 1940.
 Twenty plutonium radioisotopes have been characterized.
 The most stable are Pu-244, with a half-life of 80.8 million years, Pu-242, with a half-life of 373,300 years, and Pu-239, with a half-life of 24,110 years.
 All of the remaining radioactive isotopes have half-lives that are less than 7,000 years.
 This element also has eight meta states, though none are very stable; all meta states have half-lives of less than one second. 

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Paragraph 3 

 Livermorium (Lv) is an artificial element, and thus a standard atomic weight cannot be given.
 Like all artificial elements, it has no stable isotopes.
 The first isotope to be synthesized was Lv in 2000.
 There are four known radioisotopes from Lv to Lv, as well as a few suggestive indications of a possible heavier isotope Lv.
 The longest-lived of the four well-characterised isotopes is Lv with a half-life of 53 ms. 

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Paragraph 4 

 Darmstadtium (Ds) is a synthetic element, and thus a standard atomic weight cannot be given.
 Like all synthetic elements, it has no stable isotopes.
 The first isotope to be synthesized was Ds in 1994.
 There are 9 known radioisotopes from Ds to Ds (with many gaps) and 2 or 3 known isomers.
 The longest-lived isotope is Ds with a half-life of 9.6 seconds. 

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Paragraph 5 

 Americium (Am) is an artificial element, and thus a standard atomic weight cannot be given.
 Like all artificial elements, it has no known stable isotopes.
 The first isotope to be synthesized was Am in 1944.
 The artificial element decays into alpha particles.
 Americium has an atomic number of 95 (the number of protons in the nucleus of the americium atom). 

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Paragraph 6 

 Americium-241 (Am) is an isotope of americium.
 Like all isotopes of americium, it is radioactive.
 Am is the most common isotope of americium.
 It is the most prevalent isotope of americium in nuclear waste.
 Americium-241 has a half-life of 432.2 years.
 It is commonly found in ionization type smoke detectors.
 It is a potential fuel for long-lifetime radioisotope thermoelectric generators (RTGs).
 Its common parent nuclides are β from Pu, EC from Cm and α from Bk.
 Am is fissile and the critical mass of a bare sphere is 57.6-75.6 kilograms and a sphere diameter of 19–21 centimeters.
 Americium-241 has a specific activity of 3.43 Ci/g (curies per gram or 117.29 gigabequerels (GBq) per gram).
 It is commonly found in the form of americium-241 dioxide (AmO).
 This isotope also has one meta state; Am, with an exitation energy of 2.2 MeV, and a half-life of 1.23 μs.
 Its presence in plutonium is determined by the original concentration of plutonium-241 and the sample age.
 Because of the low penetration of alpha radiation, americium-241 only poses a health risk when ingested or inhaled.
 Older samples of plutonium containing plutonium-241 contain a buildup of Am.
 A chemical removal of americium-241 from reworked plutonium (e.g. during reworking of plutonium pits) may be required in some cases. 

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Paragraph 7 

 Naturally occurring vanadium (V) is composed of one stable isotope V and one radioactive isotope V with a half-life of 1.5×10 years.
 24 artificial radioisotopes have been characterized (in the range of mass number between 40 and 65) with the most stable being V with a half-life of 330 days, and V with a half-life of 15.9735 days.
 All of the remaining radioactive isotopes have half-lives shorter than an hour, the majority of them below 10 seconds, the least stable being V with a half-life shorter than 55 nanoseconds, with all of the isotopes lighter than it, and none of the heavier, have unknown half-lives.
 In 4 isotopes, metastable excited states were found (including 2 metastable states for V), which adds up to 5 meta states. 

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Answer: one