Question

What are the elements called which neither fit with metals or nonmetals?

Answer 1

There are various chemical and physical properties of metals and non-metals , there are $118$ elements in the periodic table which are classified into metals and nonmetals because of their properties, but some elements are there in the periodic table which exhibits properties of both metal and nonmetals.

Complete answer:
Metalloids are the smallest class of elements, metalloids fall between metals and nonmetals in the periodic table. They also fall between metals and nonmetals in terms of their properties. There are seven metalloids: Boron $(B)$, Silicon $(Si)$, Germanium $(Ge)$, Arsenic $(As)$, Antimony $(Sb)$, Tellurium $(Te)$, and Polonium $(Po)$.
Metalloids behave in chemical interaction with other elements depending mainly on the number of electrons in the outer energy level of their atoms. Metalloids have from three to six electrons in their outer energy level. Boron is the only metalloid with just three electrons in its outer energy level. It tends to act like a metal by giving up its electron in a chemical reaction. Metalloids with more than four electrons in their outer energy level tend like arsenic, antimony, and tellurium tend to act like nonmetals by gaining electrons in chemical reactions. Those with exactly four electrons in their outermost shell like silicon and germanium may act like either metals or nonmetals, depending on the other elements in the reaction.
Most metalloids have some physical properties of metals and some physical properties of nonmetals. For example- metals are good conductors of electricity, whereas nonmetals generally cannot conduct electricity. And metalloid they fall between metals and nonmetals in their ability to conduct heat, and if they can conduct electricity. They usually can do so only at higher temperatures. Metalloids that can conduct electricity at high temperatures are called semiconductors. It is used to make the tiny electric circuit in computer chips.
Metalloids tend to be shiny like metals, but brittle like nonmetals. Because they are brittle, they may chip like glass or crumble to a powder if struck. Other physical properties of metalloids are more variable, including their boiling and melting points, although all metalloids exist as solid at room temperature.

Note:
Metalloids are capable of forming glasses, when they are mixed with metals they form alloys. Metalloids have allotropes having metallic and nonmetallic allotropes; few metalloids contract when they are melted. They form compounds when they react with halogens. The reactivity of metalloid is dependent on the properties of the elements they are reacting with.