Thread: What makes a metal a metal, a nonmetal a nonmetal, and a metalloid a metalloid?

Is it basically just the elements ability to bond with itself in large clusters? And why is the P block of elements the only block with all three states of matter?

Chemical properties of an atom are determined by the number of electrons in the outer valence shell. Hydrogen, with only one electron, is a metal, though you have to freeze it solid to demonstrate its ability to conduct electricity. Lighter elements, like Li, Na, K have well defined valence shells but the screening effect of inner shells results in a more indeterminate valence in heavier elements. The explanation is really post facto, since the properties of elements were discovered and classified experimentally, and the theory developed to explain the observed properties.

I get that much. But I look at my P.T.o.E and you look at the P block and it has "metalloids" and "non-metals". What is it exactly that seperates these three different classes of matter? Just the elements ability to conduct electricity? Does it just refer to certain trends in certain physical properties? And if so which (aside from the aforementioned ability to conduct electricity)?

Thank you for your resonse as well Larry.

-Justin