To write 10-7 in standard form, you would write a decimal number with:
1s in the first 7 decimal places.
1s in the first 6 decimal places and 0 in the 7th decimal place.
0s in the first 6 decimal places and 1 in the 7th decimal place.
0s in the first 7 decimal places and 1 in the 8th decimal place.