For short time traders, how many trades can you make in a day?
No matter the type of a trader, it all depends on the number of opportunities you see during the trading session which matches your trading plan
There are times you sit for hours and make 0 trades and there are times you can get 2-3 trades in 1 session
Most important thing to note here is to make sure that you wait for signal confirmation as per your trading plan 
I guess you have to pay attention to your personal strength, and ability to make trades, you know. Novices would better do not make many trades because they have lack of experience and they have to get used to trading gradually. Actually, if we speak about scalping then I guess professionals make up to 50-100 trades per day in order to have a good staistics. Of course if you’re a novice you’d better start with 10-20 trade per day and then you have to analyze your deals properly. This will be enough for you to have an experience in scalping and decide whether this way of trading suits you or not.