Your wires would normally be black, white and bare (or green). The brass screw terminals are for the black wire, the chrome screws are for the white wire and the single green screw is for the bare (or green) ground wire. By the way, if you reverse the black and white wires your outlet will still work, but you will have a created an unsafe condition. This is also true if you reverse the white and bare wires. Al K
Answers & Comments
Your wires would normally be black, white and bare (or green). The brass screw terminals are for the black wire, the chrome screws are for the white wire and the single green screw is for the bare (or green) ground wire. By the way, if you reverse the black and white wires your outlet will still work, but you will have a created an unsafe condition. This is also true if you reverse the white and bare wires.
Al K