Bi-Color LED Red/Green and Yellow/Green

Hello,

I have 3 bi color R/G leds wired onto a breadboard and 2 wires coming from the Uno from pins 7 and 8. I have 1 100 ohm resistor connected to each wire coming from pins 7 and 8 and then each R/G bi color led is placed one behind the other. My simple sketch is this:

int bi1 = 7;
int bi2 = 8;

void setup() {

pinMode(bi1, OUTPUT);
pinMode(bi2, OUTPUT);

}

void loop() {

digitalWrite(bi1,  HIGH);
digitalWrite(bi2,  LOW);
delay (2000);
digitalWrite(bi1,  LOW);
digitalWrite(bi2,  HIGH);
delay (2000);
}

This is just an example and the green is dim and the red is brighter. Thanks in advance for suggestions.