Allotrope - two (or more) forms of the same element in which the atoms or molecules are arranged in different ways

Diamond - a form of carbon in which each carbon atom is surrounded by four other carbon atoms in the form of a tetrahedron

Ductile - the property that a metal can be drawn into wires

Giant covalent structure - In substances with giant covalent structures, millions or more atoms are held together by strong covalent bonds

Giant ionic structure - the structure of an ionic compound, which consists of oppositely charged ions packed closely together in a regular pattern called lattice

Giant metallic structure - the structure of a metal, in which ions are packed tightly together in a regular pattern to form a giant structure

Graphite - a form of carbon in which the carbon atoms are arranged in flat parallel layers.  Within each layer, each carbon atom is covalently bonded to three other atoms, forming a hexagonal arrange

Lattice - the regular pattern in which oppositely charged ions of an ionic compound are packed closely together

Malleable - the property that a metal can be hammered or rolled into thin sheets

Quartz - a crystalline form of silicon dioxide in which each silicon atom is joined to four oxygen atoms by covalent bonds while each oxygen atom is joined to two silicon atoms by covalent bonds

Simple molecular structure - the structure of a substance in which strong covalent bonds hold the atoms in each molecule together while much weaker van der Waals’ forces hold the separate molecules

Van der Waals' forces - an weak attractive force between two atoms or non-polar molecules, which arises because a fluctuating dipole moment in one molecule induces a dipole moment in the othe