Points to Ponder
- Mendeleev's periodic law is based on atomic masses of the elements.
- Modern periodic law proposed by Moslay recognizes the properties of the elements as the periodic functions of their atomic numbers.
- Elements are classified into s,p(Representative), d(transition) and f (inner transition) on the basis of modern periodic table.
- Elements following uranium are called trans uranic elements.
- Ionisation enthalpy, electron gain enthalpy, electronegativity are some of the periodic properties which regularly decreases down the group and increases along the period.
- Atomic and ionic radii are the periodic properties which increases down the group and decreases along the period.
- According to the modern periodic table, elements on the extreme left form basic oxides, those at the right forms acidic oxides and amphoteric or neutral oxides are formed by the elements in the middle.