Approximately how many elements combine in different ways to make compounds?

Approximately two elements may combine to form compounds, but there may be cases where more than two elements combine to form compounds.

Explanation:

In chemistry, the term compound is defined as a substance formed by the union of at least two elements. There are cases where more than two elements come together to form a compound, but we can say that approximately two elements are used for compound formation. An example of compound is shown in the chemical formulas H2O and FeS represent the compounds water and ferrous sulfide.

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

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