What fundamental characteristic is shared by both simple molecules like water and extended structures like salt?

They are both always solid at room temperature.

They are both formed from only one type of element.

They are both defined by a repeating atomic unit.

They both dissolve easily in all liquids.

A student observes a computer model of a substance showing atoms bonded in a vast, orderly, and continuous three-dimensional lattice. How would this material be classified?

As a collection of simple molecules

As a mixture of different elements

Because it is a gas at room temperature.

Because it contains more than one atom.

Because it is a small, self-contained group of atoms.

Because its atoms are not connected by chemical bonds.

It is made of small, discrete atomic groups.

Its atoms are arranged in a massive, repeating 3D crystal lattice.

It must be a solid substance with a very high melting point.

It is formed from a single type of atom, making it an element.