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Period 7 element facts for kids

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A period 7 element is an element in the seventh period (row) of the periodic table. It contains 32 elements, beginning at Francium and ending with Ununoctium. The Actinides are part of this period.


All elements of period 7 are radioactive. This period contains the actinides, which contains the heaviest naturally occurring element, plutonium; subsequent elements must be synthesized artificially. Whilst the first five of these are now available in macroscopic quantities, most are extremely rare, having only been prepared in microgram amounts or less. The later, transactinide elements have only been identified in laboratories in batches of a few atoms at a time.

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 francium and radium do show typical properties of their respective groups, actinides display a much greater variety of behaviour and oxidation states than the lanthanides. These peculiarities are due to a variety of factors, including a large degree of spin-orbit coupling and relativistic effects, ultimately caused by the very high positive electrical charge from their massive atomic nuclei.


Chemical element Chemical series Electron configuration Occurrence
87 Fr Francium Alkali metal [Rn] 7s1 From decay
88 Ra Radium Alkaline earth metal [Rn] 7s2 From decay
89 Ac Actinium Actinide [Rn] 6d1 7s2 From decay
90 Th Thorium Actinide [Rn] 6d2 7s2 (*) Primordial
91 Pa Protactinium Actinide [Rn] 5f2 6d1 7s2 From decay
92 U Uranium Actinide [Rn] 5f3 6d1 7s2 Primordial
93 Np Neptunium Actinide [Rn] 5f4 6d1 7s2 From decay
94 Pu Plutonium Actinide [Rn] 5f6 7s2 (*) From decay
95 Am Americium Actinide [Rn] 5f7 7s2 (*) Synthetic
96 Cm Curium Actinide [Rn] 5f7 6d1 7s2 Synthetic
97 Bk Berkelium Actinide [Rn] 5f9 7s2 (*) Synthetic
98 Cf Californium Actinide [Rn] 5f10 7s2 (*) Synthetic
99 Es Einsteinium Actinide [Rn] 5f11 7s2 (*) Synthetic
100 Fm Fermium Actinide [Rn] 5f12 7s2 (*) Synthetic
101 Md Mendelevium Actinide [Rn] 5f13 7s2 (*) Synthetic
102 No Nobelium Actinide [Rn] 5f14 7s2 (*) Synthetic
103 Lr Lawrencium Actinide [Rn] 5f14 7s2 7p1 (*) Synthetic
104 Rf Rutherfordium Transition metal [Rn] 5f14 6d2 7s2 Synthetic
105 Db Dubnium Transition metal [Rn] 5f14 6d3 7s2 Synthetic
106 Sg Seaborgium Transition metal [Rn] 5f14 6d4 7s2 Synthetic
107 Bh Bohrium Transition metal [Rn] 5f14 6d5 7s2 Synthetic
108 Hs Hassium Transition metal [Rn] 5f14 6d6 7s2 Synthetic
109 Mt Meitnerium Transition metal (?) [Rn] 5f14 6d7 7s2 (?) Synthetic
110 Ds Darmstadtium Transition metal (?) [Rn] 5f14 6d8 7s2 (?) Synthetic
111 Rg Roentgenium Transition metal (?) [Rn] 5f14 6d9 7s2 (?) Synthetic
112 Cn Copernicium Post-transition metal [Rn] 5f14 6d10 7s2 (?) Synthetic
113 Nh Nihonium Post-transition metal (?) [Rn] 5f14 6d10 7s2 7p1 (?) Synthetic
114 Fl Flerovium Post-transition metal (?) [Rn] 5f14 6d10 7s2 7p2 (?) Synthetic
115 Mc Moscovium Post-transition metal (?) [Rn] 5f14 6d10 7s2 7p3 (?) Synthetic
116 Lv Livermorium Post-transition metal (?) [Rn] 5f14 6d10 7s2 7p4 (?) Synthetic
117 Ts Tennessine Post-transition metal (?) [Rn] 5f14 6d10 7s2 7p5 (?) Synthetic
118 Og Oganesson Noble gas (?) [Rn] 5f14 6d10 7s2 7p6 (?) Synthetic
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