scl and sda like digital ports?

I can use the scl, sda, aref, gnd ports like digital ports in the arduino uno.

thanks.

I can use the scl, sda, aref, gnd ports like digital ports in the arduino uno.

scl, sda - yes aref, gnd - no

You can use gnd as a digital LOW :D

And you can use AREF as a digital input ... kind of...

You could apply a threshold voltage to an ADC pin, then set the ADC to use the AREF as the reference voltage. If the ADC reads a low value then AREF is LOW. If the ADC reads a high value, then AREF is LOW.

It's Slow and it's pointless, because it uses another input pin for the voltage, but theoretically possible.

how i can identifying the pins scl and sda , which number are?

By looking at the schematic?

But the whole question is really a moot point. SCA is directly wired to A4, and SCL is directly wired to A5. They are not distinct pins in their own right.

They only broke them out to their own header like that so that boards with different chips (such as the Due) can route the I2C pins to the same location and shields will then work with them without modification. Or that's the theory, anyway ;)