can you name a few of the first form?
Boron, silicon, germanium, arsenic, antimony, and tellurium.
Metalloid
The six commonly recognised metalloids are boron, silicon, germanium, arsenic, antimony, and tellurium. 
what is the basis of arranging the elements in the modern periodic table Atomic number, electron configuration, and recurring chemical properties. what is the purpose of the table? UNANSWERABLE why is called so? Because of the tabular display of the chemical elements. what sorts of elements can we see in it? Nonmetallic elements such as metalloids,  groups of families of elements and elements having metallic lustre.
wiki:8264375
Metalloid [SEP] Introduction
A metalloid is a type of chemical element which has a preponderance of properties in between, or that are a mixture of, those of metals and nonmetals. There is neither a standard definition of a metalloid nor complete agreement on the elements appropriately classified as such. Despite the lack of specificity, the term remains in use in the literature of chemistry. The six commonly recognised metalloids are boron, silicon, germanium, arsenic, antimony, and tellurium. Five elements are less frequently so classified: carbon, aluminium, selenium, polonium, and astatine. On a standard periodic table, all eleven elements are located in a diagonal region of the p-block extending from boron at the upper left to astatine at lower right.