Elements Less Commonly Recognized As Metalloids
There is no universally agreed or rigorous definition of the term metalloid. So the answer to the question "Which elements are metalloids?" can vary, depending on the author and their inclusion criteria. Emsley, for example, recognized only four: germanium, arsenic, antimony and tellurium. James et al., on the other hand, listed twelve: boron, carbon, silicon, germanium, arsenic, selenium, antimony, tellurium, bismuth, polonium, ununpentium and livermorium. As of 2011 the list of metalloid lists recorded an average of just over seven elements classified as metalloids, per list of metalloids, based on a sample size of 194 lists.
The absence of a standardized division of the elements into metals, metalloids and nonmetals is not necessarily an issue. There is a more or less continuous progression from the metallic to the nonmetallic. A specified subset of this continuum can potentially serve its particular purpose as well as any other. In any event, individual metalloid classification arrangements tend to share common ground (as described above) with most variations occurring around the indistinct margins, as surveyed below.
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Famous quotes containing the words elements, commonly and/or recognized:
“Nature confounds her summer distinctions at this season. The heavens seem to be nearer the earth. The elements are less reserved and distinct. Water turns to ice, rain to snow. The day is but a Scandinavian night. The winter is an arctic summer.”
—Henry David Thoreau (1817–1862)
“Accuse. To affirm another’s guilt or unworth; most commonly as a justification of ourselves for having wronged him.”
—Ambrose Bierce (1842–1914)
“The common goal of 22 million Afro-Americans is respect as human beings, the God-given right to be a human being. Our common goal is to obtain the human rights that America has been denying us. We can never get civil rights in America until our human rights are first restored. We will never be recognized as citizens there until we are first recognized as humans.”
—Malcolm X (1925–1965)