The Most Metallic Element?

Francium tile on the periodic table.

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The most metallic element is francium. However, francium is a man-made element, except for one isotope, and all isotopes are so radioactive they almost instantly decay into another element. The natural element with the highest metallic character is cesium, which is found directly above francium on the periodic table.

How Metallic Character Works

There are several properties associated with metals. The degree that an element displays these properties is its metallic character or metallicity. Metallic character is a sum of certain chemical properties, all associated with how readily an atom of an element can lose its outermost or valence electrons. These properties include:

  • Easily reduced
  • Can displace hydrogen from dilute acids
  • Forms basic oxides and chlorides

Metals also tend to be shiny, good conductors of heat and electricity, ductile, malleable, and hard, but these physical properties are not the basis of metallic character.

Periodic Table Trends for Metallic Character

You can predict the metallic character of an element using the periodic table.

  • Metallic character increases as you move down a group (column) of the periodic table. This is because atoms gain electron shell levels as you move down the table. Although there are more protons (more positive charge) as you move down a group, the outer shell of electrons is further away from the nucleus, so the valence electrons are easier to strip away from atoms.
  • Metallic character decreases as you move from left to right across a period (row) of the periodic table. This is because atoms more readily accept electrons to fill an electron shell as you move across a period. Elements on the left side of the periodic table are more likely to donate an electron than elements on the right side of the table.

Thus, the most metallic character is found in ​an element on the lower lefthand side of the periodic table.