Tennessine (Ts) is the name of element 117. Wikipedia has an article which provides a lot of information about the element. This article will focus on things Wikipedia does not stress: heavy isotopes and formation.
Maximum predicted half-lives of Ts isotopes are on the order of 1 - 2 sec, and no isotopes are predicted to be daughters of long-lived nuclides.
A large number of Ts isotopes can form during a neutron star merger or comparable event, but all of these are heavier than 324Ts, since lighter nuclides will fission at Z < 117. Supernovae are unlikely to be able to form this element.
Any Ts which does form will disappear within 316 sec of the event which led to its formation. This means that the element exists only as positive ions, except in the extraordinarily rare case of synthesis in a laboratory.
Nuclear Properties[]
Information sources[]
This article uses two main resources chosen because of their independence from one another.
At least one document maps half-life and decay mode for elements below Z = 175 from the neutron dripline down to isotopes which are too neutron-poor to survive any appreciable length of time(1). Maps on pp 15 & 18 address the entire (Z,N) region covered, but report only the dominant decay mode and report half-lives only to within a band three orders of magnitude wide (0.001 - 1 sec, for example). More detailed estimates of these properties can be extracted from maps on pp 11 & 12, but only for a limited range of Z and N. Half-life data are reported by colors, which makes numerical estimates laborious to produce. This document is connected to Japan's KTUY model.
An independent map of half-lives and decay modes exists(2). This one is limited to A = 339, as well as to Z = 132. It does not show short-lived isotopes well, and gives half-lives only within rather broad and awkward bands. It does show multiple decay modes for single nuclides. It originates from models used by the Russian agency JINR, so is completely independent of Ref. 1.
Japan Atomic Energy Agency (JAEA) maintains an on-line chart of nuclides which includes decay properties of many predicted nuclides(3) - unlike charts published by Korea Atomic Energy Research Institute (KAERI) or the (U.S.) National Nuclear Data Center (NNDC). This chart gives separate numerical values for partial half-lives against fission, beta emission (both b- and b+), and alpha emission. These appear to be systematically too long, but are probably reliable to within an order of magnitude.
Predicted properties[]
Even-N isotopes from the neutron dripline down to 380Ts decay predominantly by beta emission with half-lives in the 0.001 - 1 sec range. Half-lives aren't reported, but the properties of beta decay indicate that half-lives close to 0.001 sec are likely(4). Odd-N drops in this band decay by neutron emission.
All isotopes in the band 379Ts to 370Ts are predicted to have half-lives in the 0.001 - 1 sec range. Dominant decay modes are a mixture of fission and beta emission. Which mode dominates depends on N, with specific values of N associated with fission over a range of Z values. It is likely that both modes are significant for all isotopes.
Isotopes in the band 369Ts to 335Ts are predicted to decay by beta emission. All have half-lives in the 0.001 - 1 sec range.
Isotopes in the band 334Ts to 329Ts are predicted to have fission as their principal decay modes, but to have half-lives in the 0.001 - 1 sec range. Beta decay is likely to be a secondary decay mode for these isotopes.
328Ts to 326Ts are predicted to decay by fission and to have half-lives in the 10-06 - 0.001 sec range.
Ref 1 predicts a gap from 325Ts to 310Ts, which is predicted to be occupied by nuclear drops or very short-lived nuclides. Fission is, of course, the predicted decay mode. Ref, 2 predicts a similar gap. It does not show any stabilization near N = 198.
Between 309Ts and 306Ts, Ref. 1 and Ref. 2 agree that fission is the predominant decay mode, but differ with respect to half-lives. Ref. 1 indicates half-lives up to the 0.001 - 1 sec range, while Ref. 2 predicts half-lives under 10-06 sec.
Between 305Ts and 303Ts, Alpha decay is predicted by both sources. Ref. 1 predicts a dip in half-lives in this band. It is weak, but neutron count in this band is 188 to 186 - exactly where short alpha half-lives are to be expected above a neutron shell closure. This dip is invisible at higher Z. Ref. 3 indicates that half-lives in this band are close to, or below, 0.001 sec.
Below 303Ts, prediction of decay properties become numerous. These generally agree that alpha decay will predominate and that half-lives will peak just below 301Ts (for which N = 184). Further comparison is out of scope for this article. Ref. 3 indicates that 300Ts and 296Ts should have half-lives between 1 - 2 sec long, that 298Ts will be close to 1 sec, and that all others are shorter. It is worth noting that 295Ts and 292Ts both have predicted half-lives exceeding 0.5 sec, much longer than the observed half-lives of 294Ts and 293Ts.
The lightest isotope reported by any of Refs. 1 through 3 is 281Ts. There may be a few lighter nuclides with half-lives in the 10-14 - 10-09 sec range, but half-lives will quickly decline below the minimum needed for a nuclear drop to qualify as a nuclide.
Occurrence[]
Formation[]
All even-N nuclear drops from the neutron dripline to 382Ts are predicted to be nuclides. Some of these isotopes can form directly as a neutron star disintegrates. Most of them however require a chain of beta decays to form. From neutron dripline to 382Ts, beta decay chains pass through Ts. Between 381Ts and 367Ts, most beta decay chains terminate at Z <= 117, but most a few pass through to higher Z. A third band exists from 366Ts to 335Ts, in which beta decay chains from the neutron dripline pass through Ts. Below that is a fourth band extending from 334Ts to 293Ts in which beta decay chains from the neutron dripline are truncated by fission at Z < 117. Lighter isotopes cannot form since beta decay chains are truncated at Z < 118. It appears to be possible that material ejected from a disintegrating neutron star will allow all the nuclides to form.
Neutron capture may be able to produce nuclides up to A around 380 before fission attrition stops further growth. Neutron capture is expected to contribute to formation of all significant Ts isotopes.
Persistence[]
324Ts and heavier isotopes which can form will vanish within 1000 sec after a supernova or neutron star merger which led to their formation.
323Ts through 311Ts lie at a higher Z than the terminating nuclides of short-lived beta-decay chains in this mass range.
310Ts and lighter isotopes are predicted to have short half-lives and to be incapable of forming via beta decay from the dripline.
Atomic Properties[]
If the threshold for extinction is set at a molar concentration of 1.5E-30 - which equals [218At] in the earth as a whole - all isotopes of Ts have become extinct within 102.5 (316) sec after the event which led to their formation. At this point Ts atoms will be at a temperature on the order of 1.5E06 K(a), which is equivalent to a mean KE of 136 eV/atom. Based on predicted ionization energies and energy eigenstates, Ts will exist only as positive ions, with Ts+8 (loss of all 7s, 7p1/2, and 7p3/2 electrons) likely to be its minimum charge. It may exist - briefly - as bare nuclei, but only at emperatures above 109 K.
Tennessine has no chemical properties. It is never cool enough for the two-charge-center / bound-electron phenomena we call chemistry.
References[]
1. "Decay Modes and a Limit of Existence of Nuclei"; H. Koura; 4th Int. Conf. on the Chemistry and Physics of Transactinide Elements; Sept. 2011.
2. “Systematic Study of Decay Properties of Heaviest Elements.”; Y. M. Palenzuelaa, L. F. Ruiza, A. Karpov, and W. Greiner; Bulletin of the Russian Academy of Sciences, Physics. Vol . 76, No.11, pp 1165 – 1177; 2012
3. "Chart of the Nuclides, 2014", Japan Atomic Energy Agency; website available using "chart of nuclides" and "JAEA" as internet search terms.
4. "Nuclear Properties for Astrophysical Applications"; P. Moller & J. R. Nix; Los Alamos National Laboratory website; search by "LANL, T2", then "Nuclear Properties for Astrophysical Applications".
Notes[]
a. Except for one special case: a low-mass, population I (metal-rich) star, with a planet large enough to have an atmosphere and in an orbit which makes liquid water present in contact with both atmosphere and sunlight, several billion years to allow physicists and chemists to evolve, and a cultural willing-ness to spend vast sums of money to study Tennessine.
9-Period Periodic Table of Elements | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 | 1 H |
2 He | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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2 | 3 Li |
4 Be |
5 B |
6 C |
7 N |
8 O |
9 F |
10 Ne | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
3 | 11 Na |
12 Mg |
13 Al |
14 Si |
15 P |
16 S |
17 Cl |
18 Ar | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
4 | 19 K |
20 Ca |
21 Sc |
22 Ti |
23 V |
24 Cr |
25 Mn |
26 Fe |
27 Co |
28 Ni |
29 Cu |
30 Zn |
31 Ga |
32 Ge |
33 As |
34 Se |
35 Br |
36 Kr | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
5 | 37 Rb |
38 Sr |
39 Y |
40 Zr |
41 Nb |
42 Mo |
43 Tc |
44 Ru |
45 Rh |
46 Pd |
47 Ag |
48 Cd |
49 In |
50 Sn |
51 Sb |
52 Te |
53 I |
54 Xe | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
6 | 55 Cs |
56 Ba |
57 La |
58 Ce |
59 Pr |
60 Nd |
61 Pm |
62 Sm |
63 Eu |
64 Gd |
65 Tb |
66 Dy |
67 Ho |
68 Er |
69 Tm |
70 Yb |
71 Lu |
72 Hf |
73 Ta |
74 W |
75 Re |
76 Os |
77 Ir |
78 Pt |
79 Au |
80 Hg |
81 Tl |
82 Pb |
83 Bi |
84 Po |
85 At |
86 Rn | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
7 | 87 Fr |
88 Ra |
89 Ac |
90 Th |
91 Pa |
92 U |
93 Np |
94 Pu |
95 Am |
96 Cm |
97 Bk |
98 Cf |
99 Es |
100 Fm |
101 Md |
102 No |
103 Lr |
104 Rf |
105 Db |
106 Sg |
107 Bh |
108 Hs |
109 Mt |
110 Ds |
111 Rg |
112 Cn |
113 Nh |
114 Fl |
115 Mc |
116 Lv |
117 Ts |
118 Og | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
8 | 119 Uue |
120 Ubn |
121 Ubu |
122 Ubb |
123 Ubt |
124 Ubq |
125 Ubp |
126 Ubh |
127 Ubs |
128 Ubo |
129 Ube |
130 Utn |
131 Utu |
132 Utb |
133 Utt |
134 Utq |
135 Utp |
136 Uth |
137 Uts |
138 Uto |
139 Ute |
140 Uqn |
141 Uqu |
142 Uqb |
143 Uqt |
144 Uqq |
145 Uqp |
146 Uqh |
147 Uqs |
148 Uqo |
149 Uqe |
150 Upn |
151 Upu |
152 Upb |
153 Upt |
154 Upq |
155 Upp |
156 Uph |
157 Ups |
158 Upo |
159 Upe |
160 Uhn |
161 Uhu |
162 Uhb |
163 Uht |
164 Uhq |
165 Uhp |
166 Uhh |
167 Uhs |
168 Uho |
169 Uhe |
170 Usn |
171 Usu |
172 Usb | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
9 | 173 Ust |
174 Usq | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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(10-02-20)