So make an array, will duplicate the info of led2, led3, led4, etc.
byte ledPin[] = {2,3,4,5,10,11,12,13,}; // elements 0 to 7 << declare this with the variables
for (i=0; i<8; i=i+1){
pinMode (ledPin[i], OUTPUT);
}
and
for (i=4;i<8;i++) // 10,11,12,13 to switch
{
digitalWrite(ledPin[i], HIGH); // turn the LED on
delay(10); // wait for a second << this is 10mS; use 1000 for 1 sec
digitalWrite(ledPin[i], LOW);
delay(10);
}