Question: Can I give zakat to a poor person more than nisab amount if he/she does not have any debt?
It must not be more than nisab amount. Your zakat will be makruh if it is given more than nisab amount. If the poor person has a wife or a child, that is, if all of them are poor, the zakat can be distributed among them. If the amount given to each does not exceed nisab, it will not be makruh. It does not harm even if the child is little, on condition that he/she is poor.
Question: Is it valid to give 100 grams of gold to a poor person as zakat?
It is valid, but it is makruh to give zakat to a poor person as much as nisab amount or more than it. Gold given to a poor person as zakat should not be so much as to make him rich. However, so much zakat can be given to an indebted poor person on condition that zakat given should not be more than nisab amount after the poor person pays off his debts with it. For example, if he has debts of 80 grams of gold, it is not makruh to give him 170 grams of gold as zakat because he does not have gold as much as nisab after paying his debts.
Question: The zakat I will give to a poor person will make him rich. What should I do?
If his wife or children are poor too, you can distribute zakat among them. Alternatively, you can give him zakat . After he uses it, you can give him zakat again.
Question: Is it permissible to give 1 kilogram of gold to a poor person who has debts of 1 kilogram of gold?
Yes, it is permissible.