Why isn't opal on the periodic table?

Answer 1

The periodic table of elements is only for, well, elements. A diamond is not an element, it is a mineral. An element is a compound or molecule that cannot be broken down into anything smaller, example: hydrogen, oxygen, even gold. Diamond isn't an element therefore it cannot be in the periodic table. It is a compound composed completely of Carbon, an element with atomic number 12. Graphite is also completely composed of Carbon yet is very different to diamond in its physical and chemical properties. i.e diamond is glassy, colourless and hard, graphite is dark grey/black and is soft. This has to do with the arrangement of the carbon atoms in each compound respectively. it is not a basic element. it is a byproduct of one.
because diamond is a covalently bonded lattice of carbon atoms.

the periodic table only lists elements and not compounds so diamond is not in this, carbon (the substance diamond is made from) is.

Answer 2

Opal is not on the Periodic Table because it is a mineral composed of amorphous silica with water content. The periodic table generally lists elements, which are the most basic forms of matter, while opal is a compound made up of different elements.

Answer 3

Because 'dirt' is not a pure element, it is a mixture of many different inorganic and organic compounds.

Periodic table is for the pure elements(109) which have their own identifying properties. But dirt is impure substance which have many-things mixed together even including microorganism.

Answer 4

Diamond is a form, or 'allotrope' of the element Carbon. Carbon can form different allotropes such as graphite and fullerite, these do not appear on the Periodic table as seperate entries, they're all included under Carbon.

Answer 5

because it is not an element and the periodic table consists of elements only because it is not an element and the periodic table consists of elements only

Answer 6

The valuable substance diamond is merely a molecularly altered version of carbon, which you can find on the Periodic Table under group 4.

Answer 7

Because it is made out of carbon, which is a nonmetal.

Answer 8

For the same reason cheese isn't. It's not an element.

Diamonds are carbon, like coal. They're just arranged differently.

Answer 9

Because opal is made up of compounds like silica. The periodic table only contains single elements.

Answer 10

The periodic table only contains 'elements', not compounds. Sodium chloride is a chemically bonded compound of the elements chlorine and sodium, which do appear in the table.