How does c# keywords work?

Question

Hi there,

 

Obviously as indicated by my question I'm fairly new to programming  and seeking some clarification. Now my question is  why are keywords not called by class name? For example if I wanted to use the writeline method I first have to specify the namespace it belongs to(system) and then the class it belongs to (Console). Why are keywords exempt from this? why not   ClassName.if(){} and instead just if(){}?