Wire librairy and adress of slave device problem

Hello, I read in I²C Bus specification that two groups of eight addresses (0000XXX and 1111XXX) are reserved. But if I want to give 2 for my arduino adress (with begin(adress) function), which byte it create ?

I would like to know how wire library code the adress of the component because I want to communicate between an arduino and an other atmel component which is master of the bus.

If my atmel component want to call my arduino slave, what byte must I send to arduino?

I want to know if the 4th bits of slave adress are preconfigured in arduino component?

Best regards.