I've been wondering if it is possible to have negatively charged metal ions. Most ions tend to have electron configuratons of noble gases. So then is it possible to obtain metal ions from metal atoms by changing their electron configuration to that of the next noble gas in the periodic table? (e.g. something like Be(6-))
Yes. And, ironically, the most clear-cut examples involve alkali metals. In these compounds you have the cation, often an alkali metal itself, stabilized in a complex so that electrons can be transferred to the recipient alkali metal (Na or heavier, based on today's known compounds), and the latter is a full-fledged alkali metal anion.