Yes and No...
...since the speed of WiFi-N is higher than with WiFi-G, and the range/radius is longer, reception is notably better...
but... you will still have 'dead spots' in your reception...
...so if you have reception problems, you should first try moving your WiFi-reception antenna (i.e. your entire Mac normally) around a few inches...
if you want more in-depth info on the exact location of the 'dead spots' in your WiFi-network, try this software :
http://www.netspotapp.com