Bonding 3.1.3 Flashcards
what is ionic bonding
electrostatic force of attraction between oppositely charged ions formed by electron transfer
when is ionic bonding in ions stronger
when ions are smaller and / or have higher charges
what is a covalent bond
shared pair of electrons
what is a dative covalent bond
forms when the shared pair of electrons in the covalent bond come from only one of the bonding atoms .
what is metallic bonding
electrostatic force of attraction between the positive metal ions and the delocalised electrons
what are the 3 main factors that affect the strength of metallic bonding
1) number of protons / strength of nuclear attraction
2) number of delocalised electrons per atom
3) size of ion
what are some examples of molecules with ionic bonding ( giant ionic lattice )
Sodium chloride
Magnesium oxide
what are some examples of molecules with covalent bonding ( simple molecular )
Iodine
Ice
Carbon dioxide
water
methane
what are some examples of molecules with covalent bonding ( giant covalent )
Diamond
Graphite
silicon dioxide
what are some examples of molecules with metallic bonding ( giant metallic lattice )
All metals
how many bonds do linear shaped molecules have and its bond angle
2 bonding pairs
no lone pairs
bond angle = 180
how many bonds do trigonal planar shaped molecules have and its bond angle
3 bonded pairs
0 lone pairs
bond angle = 120
how many bonds do tetrahedral shaped molecules have and its bond angle
4 bonded pairs
0 lone pairs
bond angle = 109.5
how many bonds do trigonal pyramidal shaped molecules have and its bond angle
3 bonding pairs
1 lone pairs
bond angle = 107
how many bonds do bent shaped molecules have and its bond angle
2 bonded pairs
2 lone pairs
bond angle = 104.5
how many bonds do trigonal bipyramidal shaped molecules have and its bond angle
5 bonded pairs
0 lone pairs
bond angle = 120 and 90
how many bonds do octahedral shaped molecules have and its bond angle
6 bonded pairs
0 lone pairs
bond angle = 90
what is electronegativity
The relative tendency of an atom in a covalent bond in a molecule to attract electrons in a covalent bond to itself
what are the factors affecting electronegativity
- increases across a period as number of protons increases and atomic radius decreases because the electrons in the same shell are pulled more
- decreases down a group because the distance between the nucleus and the outer electrons increases and the shielding increases
when does a molecule become non polar
when it’s a symmetrical molecule even if the individual bonds are polar , because it’s symmetrical it will cancel out
what’s the main factor affecting size of van de waals
more electrons the higher chance temporary dipoles formed.
when do permanent dipole - dipole forces occur
in polar molecules
when does hydrogen bonding occur
compounds that have hydrogen atom attached to one of the three most electronegative atoms of nitrogen , oxygen and fluorine which must all have a lone pair of
EQ : explain how the electron pair repulsion theory can be used to deduce the shape of and the bond angle in PF3 (6)
- P has 5 electrons in the outside shell
- with 3 electrons from 3 fluorine there are a total of 8 electrons in the outside shell
- so 3 bond pairs and one non bond pair
- electrons repel as far as possible
- lone pairs repel more than bonding pairs
- therefore tetrahedral/ trigonal pyramidal shape
- with angle 109 degrees decreased to 107
