The Solid State Flashcards
The stronger the intermolecular forces, the ___________ movement of the particles
Slower
What are the properties of amorphous solids?
- random arrangement of particles
- particles have no orderly structure
- macroscopic structures lack well defined faces and shapes
- many are mixtures of molecules that do not stack up well together
- glass and rubber are examples
What are the properties of Crystalline Solids?
- atoms, ions, or molecules are arranged in an orderly fashion that follows a pattern of repetition in three dimensions
- macroscopic structures usually have flat surfaces that make definite angles to one another
- ionic solids and quarts are examples
Segments in crystalline solids that repeat in three dimensions
Unit cells
In liquids particles go thorough ____________ meaning they move around
Translation
The corners of the cubes
Lattice points
This unit cell contains:
8 corners x 1/8 of an atom
= 1 atom/unit cell
Simple cubic
This unit cell contains:
8 corners x 1/8 of an atom + 1 central
=2 atoms/unit cell
Body centered cubic
This unit cell contains:
8 corners x 1/8 of an atom + 6 faces x 1/2 of an atom
=4 atoms/unit cell
Face centered cube
What are the properties of molecular solids?
- consists of nonmetals, diatomic elements, or compounds composed of two or more nonmetals
- normally do not conduct electricity
- covalently bonded units are held together by weak intermolecular forces
- soft
- have low melting points
Why do molecular solids normally not conduct electricity
Electrons are held within the covalent bonds of each molecule
What is an example of a molecular solid?
I2
___________ fats have stronger dispersion forces, and are solid at room temperature
Unsaturated
Why do unsaturated fats have weaker dispersion forces?
A double bond bends the carbon, causing the molecule to be sp2 hybridized, therefore being trigonal planar
What is an example of a molecular solid?
Wax
One or two nonmetals held together by networks of covalent bonds instead of intermolecular forces
Covalent network solids
What are the properties of a covalent network solid?
- very hard
- very high melting points
Why are covalent network solids normally very hard?
-atoms are covalently bonded with fixed bond angles
In graphite, each carbons forms three _____ hybrid orbitals that bond with three other carbon atoms
Sp2
Graphite and diamond are __________ of each other
Allotropes
Why can sheets of graphite slide over each other so easily?
Weak pi bonds and london dispersion forces
Why does graphite have a high melting point?
The covalent bonds between carbon in each later are relatively strong
In diamond, many carbon atoms bond together with _______ hybrid orbitals
Sp3
What is the molecular geometry of diamond?
Tetrahedral
