Question

condensed (noble gas core) configuration for Ag, Br-, Ga3+

Answer 1

Here is a link to a site that gives you everything you ever wanted to know about elements and then some.
Go to the site, click on the element, then scroll down to "electron shell properties" and you're there.

Answer 2

you didn't leave a link

Answer 3

I thought I did. Sorry.
http://www.webelements.com/

Answer 4

i don't understand?

Answer 5

Ag is here.
http://www.webelements.com/silver/atoms.html

Br is here. Add one electron to the outside shell (the 4p) for Br^-
http://www.webelements.com/bromine/

Here is Ga. Subtract 3 electrons from the outside (4s and 4p).
http://www.webelements.com/gallium/