Q.10. Compare and contrast the arrangement of elements in Mendeléev’s Periodic Table and the Modern Periodic Table.
Mendeleev's periodic table |
Modern periodic table |
Elements are arranged in the increasing order of their atomic masses |
Elements are arranged in the increasing order of their atomic numbers |
Consists of 8 groups |
Consists of 18 groups |
Groups are categorised into subgroups 'a' and 'b' |
No subdivision of groups. |
Noble gases were not grouped since they were not discovered yet |
Noble gases were grouped together at the end of the table. |
There was no place for isotopes |
Slots for isotopes present according to atomic number |