Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
(a)In the modern Periodic Table, why does cobalt with higher atomic mass of 58.93 appear before nickel having lower atomic mass of 58.71?
(b) Why could no fixed position be given to hydrogen in Mendeleev’s periodic table?
(a) In the modern periodic table, elements are arranged according to the increasing atomic number. The atomic number of cobalt and nickel is 27 and 28 respectively. Hence, cobalt has a higher atomic mass and appears before nickel in the periodic table.
(b) Mendeleev’s period law failed to explain the position of hydrogen because it resembles both the properties of group 1 alkali metals and group 17 halogens. Hydrogen reacts with metals to form ionic compounds called hydrides and also with non-metals to form covalent compounds.
Updated on: 10-Oct-2022
9 Views
Advertisements