Which of the following statements are not correct? 
1) The electron gain enthalpy of F is more negative than that of CI. 
2) Ionization enthalpy decreases in a group of periodic table. 
3) The electro negativity of an atom depends upon the atoms bonded to it. 
4) ${\text{Al}}_{\text{2}}{\text{O}}_{\text{3}}$ and $\text{NO}$ are examples of amphoterie Oxides.