Even though the female only produces eggs with half the number of chromosomes, during parthenogenesis. how is she able to produce an offspring (zygote) with the full number of chromosomes?

During meiosis both females and males create gametes (sperm and egg) each gamete having 23 chromosomes from mom (the egg) and 23 chromosomes from the dad (the sperm) during fertilization the egg and sperm come together creating a child with all 46 chromosomes (not sure if this was exactly what you were asking but lol)

Normally, meiosis causes each parent to give 23 chromosomes to a pregnancy. When a sperm fertilizes an egg, the union leads to a baby with 46 chromosomes.