Find out the incorrect statement(s) :

1. All lanthanides are non-radioactive
2. Some actinides form MO2+, MO22+ oxocations
3. The compounds of lanthanides are more basic than that of actinide compounds
4. 5f elements show variable oxidation states like +2,+3,+4,+5,+6 and +7

Which law is called as the law of periods 

When light enters from one medium to another then which characteristic is not changed 

Absolute zero of temperature means

Which state has " Cyber Park"

The world's lightest material called 'Silica aerogel' or Blue air' is manufactured at