It has long been presumed that there is a common cause at the genetic, cognitive, and neural levels for autism's characteristic triad of symptoms. However, there is increasing suspicion that autism is instead a complex disorder whose core aspects have distinct causes that often co-occur.
1 Transition metals are kinds of metals that have electrons in d or f orbitals. 2  Transition metals are in columns 3-12 of the periodic table and in the lanthanide and actinide series.  Most transition metals are lustrous, silvery, hard, and good conductors; however, properties may vary greatly.
Transition Metals. 1  They can form many compounds with different oxidation states. 2  They can form compounds with different colors. 3  They are metals and conduct electricity. 4  They have high melting and boiling points. 5  They have relatively high densities. 6  They are paramagnetic. 7  The transition metal group is called the d-block of the periodic table. 8  Some