Bonding And Structure Flashcards
Which shape has 4 bonding pairs?
Tetrahedral
Which shape has 3 bonding pairs?
Trigonal planar
Which shape has 3 bonding pairs and 1 lone pair?
Trigonal pyramidal
Which shape has 2 bonding pairs and 2 lone pairs?
Bent/non-linear
Which shape has 2 bonding pairs?
Linear
Which shape has 6 bonding pairs?
Octahedral
Which shape has 5 bonding pairs?
Trigonal bipyramidal
Which shape has 5 bonding pairs and 1 lone pair?
Square pyramidal
What is the bond angle for tetrahedral?
109.5 degrees
What is the bond angle for trigonal planar?
120 degrees
What is the bond angle for trigonal pyramidal?
107 degrees
What is the bond angle for bent (water)?
104.5 degrees
What is the bond angle for linear?
180 degrees
What is the bond angle for octahedral?
90 degrees
What are the bond angles for trigonal bipyramidal?
120 degrees and 90 degrees
What is the bond angle for square pyramidal?
89 degrees
Define electronegativity
Tendency of an atom to attract a bonding pair of electrons
What are London (dispersion) forces?
Intermolecular bonds found between all simple covalent molecules, causing temporary (instantaneous) dipoles
Where do you find permanent dipoles?
In polar molecules
Which elements can form hydrogen bonds?
Hydrogen and nitrogen/oxygen/fluorine - as very electronegative
What is the bond angle for a hydrogen bond?
180 degrees (linear)
What is the octet rule?
Atoms tend to form compounds in ways which give them 8 valence electrons (like a noble gas)
What are the exceptions to the octet rule?
He - has 2 valence electrons
NO - odd number of electrons
SF6 - 1+ atoms posses more than 8 electrons
BCl3 - 1+ atoms posses less than 8 electrons
What is the expanded octet rule?
Hypervalent compounds (HCs) have more than the predicted number of bonds
They also have an expanded octet: more than 1 electron around 1 atom
What is the most electronegative element?
Fluorine
What factors effect strength and number of London forces?
More electrons in molecule = more and stronger London forces
What does having more and stronger London forces mean?
More energy is required to break the forces, so more energy is required to change physical state (eg. Melting and boiling points are higher)
