Photo AI
Many solid materials are classified as ionic, molecular, covalent or metallic crystals - Leaving Cert Chemistry - Question B - 2014
Question B
Many solid materials are classified as ionic, molecular, covalent or metallic crystals. Their properties can often be explained in terms of their crystal structures.... show full transcript
Worked Solution & Example Answer:Many solid materials are classified as ionic, molecular, covalent or metallic crystals - Leaving Cert Chemistry - Question B - 2014
Step 1
Explain the underlined term.
Answer
Regular solids are defined as materials made up of particles (atoms, ions, molecules) with faces intersecting at fixed, definite angles, characteristic of a lattice structure. These solids possess a certain packing arrangement that contributes to their stability and defined shape.
Step 2
Describe how the bonding in graphite enables it to be used for writing or as a lubricant.
Answer
Graphite consists of layers made up of hexagons of carbon atoms, held together by weak intermolecular forces, known as van der Waals forces. These layers can slide over each other easily, allowing graphite to be used for writing as the layers can rub off onto paper. This property also makes graphite an effective lubricant.
Step 3
Refer to its crystal structure to account for the hardness of diamond.
Answer
Diamond is characterized by a crystal structure where all carbon atoms are bonded by covalent bonds in a tetrahedral arrangement. This structure forms a giant interlocking network, providing exceptional strength and making diamond the hardest known natural substance.
Step 4
Explain why metals are often excellent electrical conductors.
Answer
Metals typically have outer valence electrons that are delocalized, forming a 'sea of electrons' that can move freely throughout the metal lattice. This mobility of electrons allows metals to conduct electricity efficiently.