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Actinide

Atomic No.	Name	Symbol
89	Actinium	Ac
90	Thorium	Th
91	Protactinium	Pa
92	Uranium	U
93	Neptunium	Np
94	Plutonium	Pu
95	Americium	Am
96	Curium	Cm
97	Berkelium	Bk
98	Californium	Cf
99	Einsteinium	Es
100	Fermium	Fm
101	Mendelevium	Md
102	Nobelium	No

The actinide series encompasses the 14 chemical elements that lie between actinium and nobelium on the periodic table with atomic numbers between 89 and 102 inclusive. They are similar in characteristics to the elements of the lanthanide series. The actinides with the higher atomic numbers are not found in nature and have short half-lives.

The actinides are typically placed below the main body of the periodic table, in the manner of a footnote. The full-width version of the periodic table shows the position of the actinides more clearly.