Unsepttrium | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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173Ust | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Appearance | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
unknown | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
General properties | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Name, symbol, number | unsepttrium, Ust, 173 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Pronunciation | /uːnsɛptˈtraɪəm/ | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Element category | alkali metals (predicted) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Group, period, block | 1, 8, s | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Mass number | [478] (predicted) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Electron configuration | [Usb] 6g1 (predicted)[1] 2, 8, 18, 32, 50, 33, 18, 8, 4 (predicted) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Physical properties | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
unknown | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Atomic properties | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
unknown | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Most stable isotopes | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Main article: Isotopes of unsepttrium | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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v • t • e • r |
Unsepttrium, Ust, is the temporary name for element 173. Isotopes are predicted between 492Ust and 466Ust (excluding probable artifacts), none of which have half-lives exceeding 0.001 sec. None of these predicted isotopes can form. Isotopes in the band 583Ust to 565Ust are likely, most of which may form. All Ust isotopes will be gone less than 1000 sec. after the event which led to their formation.
Nuclear properties[]
Between Z = 175 and Z near 130, one set of predictions for half-life and principal decay mode has been published[2]. [2] is publicly available and can be found via a search by paper title. Anyone interested in this element should study pp 15 and 18, which allow a given element to be understood in the context of adjacent nuclides.
These data are limited to nuclides for which N <= 333. Half-lives are presented in bands covering 3 orders of magnitude (0.001 sec to 1 sec, for instance) and are accurate to within +/- 3 orders of magnitude, which seems rather crude until the enormous extrapolation from what is known is taken into account, Minimum half-life is set at 10-9 sec, rather than 10-14 sec; which introduces a little uncertainty, but not a great deal because fission half-lives tend to transition quickly from values well above 10-9 sec to values well below 10-14 sec; and, while alpha-decay half-lives change more slowly, alpha emission is rarely dominant except where fission is suppressed. Significantly, beta-decay half-lives do not decline far below 103 sec, even for highly energetic decays, so there is little uncertainty about neutron-rich nuclides.
[2] does have one significant weakness. Nuclides which are beta-stable are identified by black squares, overwriting decay mode and half-life information. In many cases, these data can be estimated from adjacent nuclides.
No predictions exist for N > 333. The approach used for Z = 176 and above can be used at lower Z.
A boundary in the (Z,A) plane is constructed in The Final Element defining a region of that plane outside of which no nuclei exist. It does not predict where nuclei can exist within that region; but the first-order, liquid-drop model used to create that boundary can be used to guess at where nuclides may exist. Criteria used to guide these guesses are described in Nuclear Guesswork. The resulting A(Z) ranges developed should not be considered accurate, but they are consistent from element to element.
Predicted properties[]
[2] predicts isotopes ranging from 505Ust to 440Ust.
505Ust and 502Ust appear to be artifacts. N = 318 has been predicted[3] to be a neutron closure, but N = 229 or 232 is far above that closure.
501Ust to 493Ust is a gap, which might mean half-lives below 10-9 sec or might mean the model is going ragged at its edges.
492Ust decays by alpha emission and is estimated from adjacent nuclides to have a half-life in the ns-ms range. A second gap from 491Ust to 488Ust separates the two bands. This gap, too, may reflect short alpha-decay half-lives or a breakdown of the model.
The main band lies between 487Ust and 470Ust. Format used to display these is: isotope(s); half-life in seconds; dominant decay mode; comments.
487Ust - 483Ust; 10-9 - 0.001; alpha; These are not unrealistic, particularly if N = 318 is also neutron-magic like N = 308, Half-lives are estimated from adjacent nuclides.
482Ust - 474Ust; 10-6 - 0.001; alpha; Some half-lives, including those at the band edge must be estimated from adjacent nuclides.
473Ust - 468Ust; 10-9 - 10-6; alpha. Some half-lives, including those at the band edge must be estimated from adjacent nuclides.
467Ust - 466Ust; 10-9 - 10-6; fission.
This pattern is to be expected, given a neutron shell closure at N = 308.
440Ust is reported to decay mainly by proton emission and have a half life in the 10-6 to 0.001 sec range. Its long half-life implies strongly that it is an artifact.
Guessed properties[]
A nuclear drop containing 173 protons and more than 579 neutrons must decay by neutron emission with a half-life under 10-14 sec. A drop with 173 protons and fewer than 228 neutrons must decay by spontaneous fission with a half-life under 10-14 sec. Nuclear drops in the band from 752Ust to 401Ust are not required to decay either by neutron emission or by fission, so it is possible they will survive the 10-14 sec needed for them to become nuclides.
Nuclear drops in the band 752Ust to -674Ust are likely to decay by neutron emission but are stable against fission. Nuclides in this band are unlikely. Drops in the band -673Ust to -629Ust are likely to decay by neutron emission and require a moderate amount of structural correction energy. Nuclides in this band are improbable.
Drops in the band 583Ust to 565Ust, and also 481Ust are unlikely to decay by neutron emission and are stable against fission. Nuclides in these bands are likely. Drops in the bands -628Ust to 584Ust, 564Ust to 482Ust, and 480Ust to 455Ust are unlikely to decay by neutron emission and require a moderate amount of structural correction energy. Nuclides in these bands are unlikely. Drops in the band 454Ust to 401Ustare unlikely to decay by neutron emission but require large structural correction. Nuclides in this band are improbable.
Comparison[]
The two techniques described above were more or less consistent. [2] does predict far more nuclides than were estimated to be "likely". The technique for estimating where nuclides are likely to exist is conservative.
Occurence[]
Formation[]
583Ust to 565Ust are likely to be nuclides. Depending on the neutron dripline's actual location, nuclei in this A range may form when material over 700 - 800 meters deep is ejected from a neutron star during a merger. (See Neutron Star.). Heavier Ust isotopes may form directly. Isotopes 579Ust to 565Ust are likely to form via beta decay chains from lower Z nuclides, although attrition due to fission or beta+neutron(s) decay can be expected.
Many nuclear drops in the band 505Ust to 440Ust are predicted to be nuclides. They are all too far from the neutron dripline to form directly, and cannot form from lower Z nuclides because beta decay chains terminate at Z < 173.
It is implausible that neutron capture can form any Ust isotope.
Persistence[]
All Ust isotopes are expected to decay away to nothing within 1000 sec after the neutron star merger which led to their formation.
Atomic properties[]
Electron structure of Ust has received limited study, but it is likely to differ significantly from what's found at lower atomic numbers. It is likely that orbital theory breaks down between Z = 170 and Z = 175. (Z = 173 is the most probable value at which this theory breaks down.) While only the innermost electrons would be qualitatively different, other orbitals are likely to be affected sufficiently to change the ground state occupation. Ust is also large enough that nuclear shape may have an effect on electron structure, which might cause different isotopes of Ust to have different electronic structures. (That means it is no longer an element in the chemical sense.) Predictions of atomic or chemical properties of Ust are risky.
If these effects are small, and if the assumptions made in Period 9 Elements are valid, Ust will be the 9th period alkali metal.
References[]
- ↑ Electron configurations of the elements_(data page) - Wikipedia
- ↑ 2.0 2.1 2.2 2.3 2.4 "Decay Modes and a Limit of Existence of Nuclei"; H. Koura; 4th Int. Conf. on the Chemistry and Physics of Transactinide Elements; Sept. 2011.
- ↑ “The Highest Limiting Z in the Extended Periodic Table”; Y.K. Gambhir, A. Bhagwat, and M. Gupta; Journal of Physics G: Nuclear and Particle Physics. 42 (12): 125105. DOI:10.1088/0954 3899/42/12/ 125105.
Other references are found in the wiki articles cited.
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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(06-07-20)