Metallic character decreases as you move across the periodic table from left to right. This occurs as atoms more readily accept electrons to fill a valence shell than lose them to remove the unfilled shell. Metallic character increases as you move down the periodic table. This is due to the fact that the electrons become easier to lose as the atomic radius increases. The increase in atomic radius decreases attraction between the positive nucleus and the negative electrons, causing the electrons to be held more loosely.