FlameSparkZ: Not necessarily. The weakness to impact attacks might come from the fact that pure silver is extremely soft and malleable, though it's strange why silver is weak to corrosion when that's the opposite in real life. I don't think the attributes are based on the real life properties of the metal they are tied to. While silver was vulnerable to electric attacks because it is a good conductor of electricity, it's strong against heat-based attacks, even though it's a good conductor of heat.
MeisterBabylon: Well, at the end of the day, MtG card naming conventions should stand secondary to what is considered "correct" by canon, but it's your character, so just go with whichever you feel sounds right.