- Home/
- CDS & Defence/
- Article
Atomic numbers of Actinides are from _____. (a) 57 – 70 (b) 58 – 71 (c) 89 – 103 (d) 89 – 102
By BYJU'S Exam Prep
Updated on: September 25th, 2023
Atomic numbers of Actinides are from 89-103. Actinides have atomic numbers ranging from 89 to 103. Actinides consist of 15 elements and range in composition from actinium to lawrencium. Group 3 frequently contains actinium (atomic number 89), and the f-block actinides begin with thorium (atomic number 90), bringing the total number of elements down to 14.
Table of content
Atomic numbers of Actinides
- The word actinide refers to a group of elements that are actinium-like, including Ac, Th, Pa, U, Np, Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No, and Lr.
- Uranium and thorium are the two naturally occurring radioactive elements, and all actinides are radioactive by nature.
- The first series of the f-block, or the lanthanides, has atomic numbers 58-71.
- The first lanthanide is lutetium, and the last lanthanide is lanthanum.
- But like Actinium, Lanthanum (atomic number 57) is a member of group 3 and is not a part of the f-block.
- As a result, the lanthanides in the f-block range from 58 to 71.
- Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu are all members of the lanthanide series.
Summary:
Atomic numbers of Actinides are from _____. (a) 57 – 70 (b) 58 – 71 (c) 89 – 103 (d) 89 – 102
Actinides have atomic numbers ranging from 89 to 103. Actinides have a wide range of physical characteristics, including changeable valency, and very high atomic and ionic radii.