Is there any way to make the arrow keys to act as a mouse?
If you want to be able to change hitting and placing of blocks then yes, you would hit
esc on your key board. Go to options then controls, ...Go to gameplay, click on what you want to change and press the key you want to change it to.
You can have keys act as a mouse, but it really doesn't have anything to do with Minecraft to be able to have a mouse as keys on your computer. This link has a step by step instructions for all windows users on how to make your numeric keys work as a mouse. http://www.computerhope.com/issues/ch000542.htm