I have no knowledge about this breed, but my quick google search suggests an adult morkie should weigh 4+ pounds. I've included a small chunk of the information from the articles I found and underlined the paragraph is the link to the source. I'd call a local vet just to be sure if I were you.
The Morkie usually weighs between 4 and 8 pounds and is generally 6 to 8 inches tall at the withers. The big difference in potential size depends on which breed your Morkie puppy takes up after- Maltese or Yorkshire Terrier. Either way, this is a very small dog. Only their personality is large and trust us, that’ll do!