Dative covalent and coordinate covalent

Strongest attractive force between two ammonia molecules

Hydrogen bonds

Draw a diagram to show how two ammonia molecules interact with each other in the liquid phase

State how the bond between the ammonia and boron trichloride is formed

Lone pairs on NH3 is donated to B(Cl3)

Explain why iodine has a higher melting point than fluorine 

Iodine has more electrons 

stronger/ more vDW forces in between molecules 

Draw shape of NHF2

Trigonal pyramid

Draw shape of BF3

Trigonal planar

Suggest a value for the F-N-F bond angle in NHF2

107

How dative covalent bond is formed?

Lone pair on N(HF2) donated to BF3

State how two carbon atoms form a carbon-carbon bond in graphene

shared pair of electrons from each C atom

empirical formula of graphene

CH

Draw the shape of BrF3 and predict its bond angle

Trigonal planar 

120 

or if T shaped shown its 90

Fluorine reacts with bromine to form liquid bromine trifluoride (BrF3)

state the type of bond between Br and F in BrF3, 

state how this bond is formed

Covalent 

shared pair of electrons from Br and one electron from F 

Draw the shape of BrF4- and predict its bond angle

90

BrF4- ions are also formed when potassium fluoride dissolves in liquid BrF3 to form KBrF4

explain in terms of bonding, why KBrF4 has a high melting point

Ionic forces of attraction between ions

strong electrostatic attractions 

lots of energy needed to break bonds 

between K+ and BrF4- ions 

Draw a diagram to show how two molecules of hydrogen fluoride are attracted to each other by the type of intermolecular forces

Explain why the boiling point of fluorine is very low

simple molecules

weak vDW forces in between molecules

little energy needed to overcome

Draw the shape of the PH3 molecule

State the type of bond formed between the PH3 molecule and the H+ ion

dative covalent bond

pair of electrons on P(H3) donated to H+

Bond angle in the PH4+ ion

109.5

Although phosphine molecules contain hydrogen atoms, there is no hydrogen bonding between phosphine molecules

difference in electronegativity between P and H is too small

Write an equation for the formation of aluminium chloride from its elements

Al + 1.5 Cl2 —> AlCl3

Name the type of bond and explain how this type of bond is formed in the AlCl4- ion

dative covalent bond

electron pair on Cl- donated to Al(Cl3)

Aluminium chloride has a relative molecular mass of 267 in the gas phase

deduce the formula of the aluminium compound that has a relative molecular mass of 267 

Al2Cl2 

AlBr3

Deduce the name or formula of a compound that has the same number of atoms the same number of electrons and the same shape as the AlCl4- ion 

SiCl4

silicon tetrachloride 

Shape of TlBr5 2- ion

trigonal bipyramidal

Draw shape of the TlCl2+ ion

Cl- Tl - Cl

linear

Explain why the TlCl2+ ion has the shape (linear)

2 B.P of electrons repel equally 

electrons in the bonds repel to be as far apart as possible