C3 Structure and Bonding Flashcards
What is ionic bonding and where does it occur?
Ionic bonding occurs between metal and non metal atoms and they contain oppositely charged ions held together by electrostatic forces of attraction
How is sodium chloride a ionic compound and what structure does it contain?
It is ionic compound as it made up of Na+ and Cl- ions. Sodium loses an electron whilst chlorine gains an electron to produce ions with a full outer electron shell. This forms a ionic lattice structure with a cubic shape and a giant repeating pattern. It is a giant ionic structure
Name 5 common compound ions and there charges
OH- hydroxide
NO3 - Nitrate
NH4+ - Ammonium
SO4 2- Sulfate
CO3 2- Carbonate
What are the features of ionic compounds?
High melting point due to strong forces of electrostatic attraction so a lot of energy is needed to break these bonds
Conducts electricity when molten or dissolved in solutions as ions are free to move round
What is covalent bonding?
CB is the sharing of the outer electron in order for an atom to obtain a full shell.
What type of charges do covalent bonds contain?
Electrostatic attraction between shared electrons and positive nucleus
What is a dative covalent bond/Coordinate bond?
It is one atom donate 2 electrons to an atom or ion to form a bond
Name a example of a compound which contains a coordinate bond?
NH4+
Name 2 types of Giant covalent structures
Graphite and Diamond
How is Graphite bonded and what are the features?
Each Carbon is bonded 3 times with the 4th electron being delocalised containing lots of strong covalent bonds. The layers slide easily due to weak forces between layers. It can conduct electricity as the delocalised electron can carry a charge. It has a low density and soluble
How is Diamond bonded and what are the features?
Each carbon is bonded 4 times in a tetrahedral shape and it is tightly packed and rigid. It is a great conductor of heat and contains a very high melting point. It does not contain electricity as there are no delocalised electrons
How are shapes of molecules determined?
The shape of a molecule is determined by the number of electron pairs around the central atom. Each electron pair naturally repels each other so that the largest bond angle exists between covalent bonds
Name all the molecule shapes and bond angles?
Linear 180
V shaped 104.5
Trigonal planar 120
Triangular pyramid 107
Tetrahedral 109.5
Trigonal bipyramid 90 and 120
Octahedral 90
Name a compound for each molecule shape?
Linear - BeCl2
V shaped - H2O
Trigonal planar - BF3
Triangular pyramid - NH3
Tetrahedral - CH4
Trigonal Bipyramid - PCl5
Octahedral - SF6
What is electronegativity?
It is ability of an atom to attract electrons towards itself in a covalent bond
Bigger the difference in electronegativity
More polar the bond
Why is H2O polar?
Due to uneven distribution
What is the order of IMF in order of decreasing weakness?
Hydrogen bonding
Permanent dipole dipole forces
VDW
What are VDW forces?
They are the weakest IF force actings as a induced dipole dipole between molecules
What are permanent dipole forces?
This force acts between polar bonds. The delta + and delta - regions attract each other and hold each other in a lattice like structure
What is hydrogen bonding and name a compound where it occurs?
This is the strongest type of IF and these bonds form between hydrogen and the three electronegative atoms nitrogen oxygen and fluorine. Water is a example
How does metallic bonding occur?
They contain giant metallic lattice structures held together by electrostatic forces of attraction between + metal ions and - delocalised electrons. Positive metal ions are surrounded by a sea of delocalised electrons
Features of Compounds that contain metallic bonds?
High MP due to strong esf
Good electrical conductor due to sea of delocalised electrons
Good thermal conductors as delocalised electron can transfer ke
