Topic 2 - structure and bonding Flashcards
Name for positive and negative ions
positive - cation
negative - anion
Ionic compounds structure
shape, forces, charge
lattice.
oppositely charged ions are attracted into a lattice that gets biggrt until it consists of millions of ions
- non direction forces
metallic bonding structure
electrons, forces, bonding, arrangemeny
- each metal loses its valence electron (s)
these electrons move freely through the kattice between the positively charged metal ions - strong electrostatic forces of attraction
- 3D lattice with non- directional bonding
What state is metal in at room temp ? why?
forces, mp bp
Electrostatic force of attration of the metallic bond is strong and requires a lot of energy to over come. Results in a high melting and boiling point
Are metals good conductors of heat and electricity ? why?
electrons
Have electrons that are mobile/ delocalised, which can carry a charge or heat energy through the metal.
What is the mobility of metals ? why?
electrons.
Surrounded by a sea of delocalised electrons. When the slightly positive metal atoms are deformed (molded or pulled into wires), the free moving electrons flow around them, shielding the slightly positive atoms from each other.
What is the state of covalent molecualr structures at room temp? why?
mp bp, bonds,energy
- Liquid or gases at room temperature
- Low melting and boiling points
Substances are made up of simple molecules. Atoms are joined by covalent bonds; molecules have weak intermolecular force.
Not much energy is needed to separate the molecules from each other.
What is the solubility of covalent molecular structures ?
- Not many soluble in water
- Soluble in organic solvents
Covalent molecular substances dissolve in covalent molecular substances
Are covalent molecular substances good conductors ? why?
particles, charges
Cannot conduct
no mobile charged particles
What is the state of ionic substances at room temperature?Why?
mp bp, arrangement, attraction, energy
- Crystalline solids at room temperature
- High melting/ boiling points
- Regular arrangement of ions in a lattice (positive, negative ions)
- Ions are attracted to each other by strong electrostatic force of attraction.
- Large amounts of energy is needed to overcome and separate ions.
Are ionic substances soluble? why?
- Most soluble in water
- Not soluble in organic solvents
Water is attracted to the positive and negative ions and so will dissolve
Are ionic substances good conductors ? why?
Can conduct when molten or in solution – has mobile ions.
What allows a substance to conduct electricity ?
contain free moving charged particles. Charged particles cam be ions or electrons.
Structure of simple molecular substances
what atoms, bonds
made up of a small number of non-metal aroms, held together by strong covalent bonds.
bonds and force strength in simple molecualr substances
forces, bonds
covalent bonds between non metal atoms are very strong, forming individual molecules
held together by weak attractive forces
Giant covalent substances structure
bonds, element types
networks made up of a large number of non-metal atoms, held together with a very large number of covalent bonds
Bond and force strength of giant covalent substances
outlier
covalent bonds are very strong
Ony graphite has weak attractive forces
What is an Allotrope?
two or more different physical forms of an element can exist
What is the structure of diamond?
allotrope of what? bond, arrangement
allotrope of carbon.
Each atom is covalently bonded to 4 other carbon atoms in a tetrahedral arrangement
properties and uses of diamond
strength, bonds, used in
very strong and hard because of the large number of strong covalent bonds which are hard to break
used in cutting tools
What is the structure of graphite?
allotrope of , bonds, arrangement
allotrope of carbon
each atom is covalently bonded to 3 other carbon atoms ina hexagonal arrangement
each layer is a 2D giant molecule
force strength of graphite
layers, electrons bond
between the layers are weak forces of attraction due to the remaining electron that is not bonded to any particular carbon atom.
properties and uses of graphite
layers,
break easily, layers slide over eachother
used as a lubricant and in penicls
is graphite a good conductor?
yes, due to delocalised electrons between layers
structure of silicon oxide
bonds with what, arrangement,
formed when silicon atoms covalently bond to 4 oxygen atoms in a tetrahedral arrangement
Properties of silicon oxide
similar, strength, mp.
simialr to diamond
hard with a high melting point
