Period 7 element
| Part of a series on the |
| Periodic table |
|---|
A period 7 element is one of the
Properties
All elements of period 7 are
Although the rarity of many of these elements means that experimental results are not very extensive, their periodic and group trends are less well defined than other periods. Whilst
Elements
Chemical element Block Electron configuration Occurrence 87 Fr Francium s-block[Rn] 7s1 From decay 88 Ra Radium s-block[Rn] 7s2 From decay 89 Ac Actinium f-block[Rn] 6d1 7s2 (*) From decay 90 Th Thorium f-block[Rn] 6d2 7s2 (*) Primordial 91 Pa Protactinium f-block[Rn] 5f2 6d1 7s2 (*) From decay 92 U Uranium f-block[Rn] 5f3 6d1 7s2 (*) Primordial 93 Np Neptunium f-block[Rn] 5f4 6d1 7s2 (*) From decay 94 Pu Plutonium f-block[Rn] 5f6 7s2 From decay 95 Am Americium f-block[Rn] 5f7 7s2 Synthetic 96 Cm Curium f-block[Rn] 5f7 6d1 7s2 (*) Synthetic 97 Bk Berkelium f-block[Rn] 5f9 7s2 Synthetic 98 Cf Californium f-block[Rn] 5f10 7s2 Synthetic 99 Es Einsteinium f-block[Rn] 5f11 7s2 Synthetic 100 Fm Fermium f-block[Rn] 5f12 7s2 Synthetic 101 Md Mendelevium f-block[Rn] 5f13 7s2 Synthetic 102 No Nobelium f-block[Rn] 5f14 7s2 Synthetic 103 Lr Lawrencium d-block[Rn] 5f14 7s2 7p1 (*) Synthetic 104 Rf Rutherfordium d-block[Rn] 5f14 6d2 7s2 Synthetic 105 Db Dubnium d-block[Rn] 5f14 6d3 7s2 Synthetic 106 Sg Seaborgium d-block[Rn] 5f14 6d4 7s2 Synthetic 107 Bh Bohrium d-block[Rn] 5f14 6d5 7s2 Synthetic 108 Hs Hassium d-block[Rn] 5f14 6d6 7s2 Synthetic 109 Mt Meitnerium d-block[Rn] 5f14 6d7 7s2 (?) Synthetic 110 Ds Darmstadtium d-block[Rn] 5f14 6d8 7s2 (?) Synthetic 111 Rg Roentgenium d-block[Rn] 5f14 6d9 7s2 (?) Synthetic 112 Cn Copernicium d-block[Rn] 5f14 6d10 7s2 (?) Synthetic 113 Nh Nihonium p-block[Rn] 5f14 6d10 7s2 7p1 (?) Synthetic 114 Fl Flerovium p-block[Rn] 5f14 6d10 7s2 7p2 (?) Synthetic 115 Mc Moscovium p-block[Rn] 5f14 6d10 7s2 7p3 (?) Synthetic 116 Lv Livermorium p-block[Rn] 5f14 6d10 7s2 7p4 (?) Synthetic 117 Ts Tennessine p-block[Rn] 5f14 6d10 7s2 7p5 (?) Synthetic 118 Og Oganesson p-block[Rn] 5f14 6d10 7s2 7p6 (?) Synthetic
(?) Prediction
(*) Exception to the
In many periodic tables, the f-block is erroneously shifted one element to the right, so that lanthanum and actinium become d-block elements, and Ce–Lu and Th–Lr form the f-block tearing the d-block into two very uneven portions. This is a holdover from early erroneous measurements of electron configurations.[2] Lev Landau and Evgeny Lifshitz pointed out in 1948 that lutetium is not an f-block element,[3] and since then physical, chemical, and electronic evidence has overwhelmingly supported that the f-block contains the elements La–Yb and Ac–No,[2][4] as shown here and as supported by International Union of Pure and Applied Chemistry reports dating from 1988[4] and 2021.[5]
S-block
Francium and radium make up the s-block elements of the 7th period.
Francium (Fr, atomic number 87) is a highly
Radium (Ra, atomic number 88) is an almost pure-white
Actinides
The actinide or actinoid (IUPAC nomenclature) series encompasses the 15 metallic chemical elements with atomic numbers from 89 to 103, actinium through lawrencium.[9][10][11][12]
The actinide series is named after its first element actinium. All but one of the actinides are
Of the actinides,
All actinides are
In presentations of the
Transactinides
Transactinide elements (also, transactinides, or super-heavy elements) are the chemical elements with atomic numbers greater than those of the actinides, the heaviest of which is lawrencium (103).[15][16] All transactinides of period 7 have been discovered, up to oganesson (element 118).
Transactinide elements are also transuranic elements, that is, have an atomic number greater than that of uranium (92), an actinide. The further distinction of having an atomic number greater than the actinides is significant in several ways:
- The transactinide elements all have electrons in the 6d d-block).
- Even the longest-lasting isotopes of many transactinide elements have extremely short half-lives, measured in seconds or smaller units.
- The element naming controversy involved the first five or six transactinide elements. These elements thus used three-letter systematic namesfor many years after their discovery had been confirmed. (Usually, the three-letter symbols are replaced with two-letter symbols relatively shortly after a discovery has been confirmed.)
Transactinides are radioactive and have only been obtained synthetically in laboratories. None of these elements has ever been collected in a macroscopic sample. Transactinide elements are all named after nuclear physicists and chemists or important locations involved in the synthesis of the elements.
Chemistry Nobel Prize winner
IUPAC defines an element to exist if its lifetime is longer than 10−14 seconds, the time needed for the nucleus to form an electronic cloud.[17]
Notes
- ^ Some elements discovered through synthesis, such as technetium, have later been found in nature.
References
- ^ "Periodic Table – Royal Society of Chemistry". www.rsc.org. Retrieved 2023-10-19.
- ^ .
- ^ L. D. Landau, E. M. Lifshitz (1958). Quantum Mechanics: Non-Relativistic Theory. Vol. 3 (1st ed.). Pergamon Press. pp. 256–7.
- ^ (PDF) from the original on 25 March 2012. Retrieved 24 March 2012.
- (PDF) from the original on 13 April 2021. Retrieved 9 April 2021.
- ^ "Francium | Radioactive, Alkali Metal, Rare | Britannica". www.britannica.com. Retrieved 2023-10-19.
- ^ Luis A. Orozco (2003). "Francium". Chemical and Engineering News.
- ^ The Manhattan Project. An Interactive History. US Department of Energy
- ^ ISBN 978-1-57912-814-2.
- ^ Actinide element, Encyclopædia Britannica on-line
- ^ Although "actinoid" (rather than "actinide") means "actinium-like" and therefore should exclude actinium, that element is usually included in the series.
- ISBN 978-0-85404-438-2.
- ^ Greenwood, p. 1250
- .
- ^ IUPAC Provisional Recommendations for the Nomenclature of Inorganic Chemistry (2004) Archived 2006-10-27 at the Wayback Machine (online draft of an updated version of the "Red Book" IR 3–6)
- ISBN 978-1-4020-3555-5.
- ^ "Kernchemie".
