Aluminum is an element. which best describes what makes up a sample of aluminum?
a. one kind of atom
b. two different kinds of atoms
c. all carbon-based atoms
d. a carbon atom and non-carbon atoms

A sample of aluminium element is composed of one kind of atom.

An element is an example of a pure sample. In an element, there is only one type of atom present and that is the atom that composes the element.

So, in a sample of aluminium element, we only expect to see aluminium atoms which compose the element.

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the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.