Chapter 4 - Chemical bonding Flashcards
What is dative/coordinate bonding?
When the two shared electrons come from the same atom
What angle and shape does a molecule with two bond pairs make?
180 degrees, and linear
What angle and shape does a molecule with three bond pairs make?
120 degrees, and trigonal planar
What angle and shape does a molecule with four bond pairs make?
109.5 degrees, and tetrahedral
What angle and shape does a molecule with five bond pairs make?
120 and 90 degrees, and trigonal bipyramid
What angle and shape does a molecule with six bond pairs make?
90 degrees, octahedral
What angle and shape does a molecule with three bond pairs and 1 lone pair make?
107 degrees, and pyramidal
What angle and shape does a molecule with two bond pairs and 2 lone pairs make?
104.5 degrees, and bent/angular
What is an examples of bent molecules?
water
What angle and shape does a molecule with four bond and 2 lone pairs make?
90 degrees, and square planar
What is the formula of ammonia
NH3
What is the formula of ammonium
NH4
What are the three main types of intermolecular forces?
Hydrogen bonds, Van der Waals, permanent dipole-dipole forces
What is another name for ionic bonds?
Electrovalent bonds
What do bond lengths depend on?
How strong the force of attraction is, which results in a stronger bond
What do the shape of bond angles depend on?
The numbers of electron pairs and bond pairs surrounding each atom
Which bond occurs when hybridized orbitals overlap linearly?
Sigma bonds
Which bond occurs when hybridized orbitals overlap sideways ?
pi bonds
Describe the attraction forces between metallic bonding
a regular lattice structure made up of strong electrostatic forces between positive charges and the negative charges of delocalised electrons
What are the factors that increase the strength of metallic bonding
increasing positive charge on the ions, decreasing the size of metal ions, increasing numbers of mobile electrons per atom
Which are more reactive, dipoles or non-polar molecules?
Dipoles
Why can graphite conduct electricity, and graphite cannot?
Graphite has delocalised electrons, while diamond does not
What causes the increase of Van der Waals’?
Increased number of electrons (and the protons),
Increasing the number of contact points between molecules (work best will crystalline structures)
Which elements are needed to be present for hydrogen bonding to occur?
Fluorine, oxygen or nitrogen, that have an available lone pair
What properties did hydrogen bonding give water?
High enthalpy change of evaporation and boiling point, surface tension and viscosity, ice is less dense than water (because of the three-dimensional hydrogen bonded network of water molecules)
What are some properties of covalent bonds in room temperature?
they are usually liquid or gas, they have low melting points, low boiling points, and low enthalpy changes of vaporisation. If they are solid in room temperature that means that their Van der Waal forces are very high
What interaction occurs when ionic bonds dissolve in water?
ion-dipole interactions
