int relayPin[] = {1,2,3,4,5,6,7,8,9,10}; //we create an array for all those pins
int delayValue = 100;

void setup() {
//define all pins as output pins
  for(int i = 0; i < 10; i++){
  pinMode(relayPin[i],OUTPUT);
  }
}

// Loops through the pins
void loop() {
  for(int i = 0; i < 10; i++){ 
  digitalWrite(relayPin[i], LOW);
  delay(delayValue);
  digitalWrite(relayPin[i], HIGH);
  delay(delayValue);
  }
}