Fraction = (Weight of 500 grams) / (Total weight of 1 kg)
Fraction = 500 grams / 1000 grams
Simplifying the fraction by dividing both the numerator and denominator by 500:
Fraction = 500 grams / 500 / 1000 grams / 500
Fraction = 1 / 2
Therefore, 500 grams is one-half or 1/2 of 1 kg.