1.3-1.6 Flashcards
what is the definition of the octet rule
when forming a compound an atom tends to gain, lose or share electrons in its outer shell to achieve eight in its outershell
what is the definition of Ionic bonding
the electrostatic attraction between oppositely charged ions formed by electron transfer
what is the structure of ionic bonding
giant ionic lattice
we say that ionic bonds are what
non-directional
what is the definition of metallic bonding
metallic bonding is the attraction between positive ions and delocalised electrons in a lattice
what is the definition of delocalised electrons
delocalised electrons are outer shell electrons that do not have fixed positions but move freely
what is the structure of metallic bonding
giant metallic lattice
covalent bonding definition
A covalent bond is the electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms
lone pair definition
A lone pair is a pair of unshared electrons in the outer shell of an atom
coordinate covalent definition
A coordinate covalent bond is a shared pair of electrons between two atoms with both electrons shared by one of the two atoms.
2 compounds that have giant covalent lattices
Diamond and graphite
Diamond bonding description
each carbon atom is covalently bonded to 4 others in a tetrahedral arrangement
Graphite bonding description
each carbon is covalently bonded to 3 others forming layers arranged in hexagons. Between separate layers there are weak v.d.w. Each carbon therefore has 1 electron not involved in bonding which are free to move and carry charge.
VSEPR expanded
valence shell electron pair repulsion theory
2 bonding
180
linear
symmetrical
3 bonding
120
trigonal planar
symmetrical
4 bonding
109.5
tetrahedral
symmetrical
5 bonding
120, 90, 180
trigonal bipyramidal
symmetrical
6 bonding
90, 180
octahedral
symmetrical
3 bonding 1 lone
107
Pyrammidal
unsymmetrical
2 bonding 2 lone
104.5
bent
unsymmetrical
3 bonding 2 lone
80
T-shaped
unsymmetrical
4 bonding 2 lone
90
square planar
symmetrical
2 bonding 3 lone
180
linear
symmetrical
definition of electronegativity
electronegativity is the extent to which an atom attracts the bonding pair of electrons in a covalent bond to itself
electronegativity across periods and down groups
increase across
decrease down
if electrons are equally shared it is……
non polar
However if 2 different number of electrons it is
polar
The most electronegative element is
fluorine
definition of a polar bond
A polar bond is a covalent bond in which there is an unequal sharing of the bonding electrons
what is the definition of a hydrogen bond
A hydrogen bond is the attraction between a lone pair of electrons on a very electronegative atom on one molecule and a neighbouring hydrogen on a neighbouring molecule in which the hydrogen is covalently bonded to a very electronegative atom.
what are the elements which can form a hydrogen bond
N, O, F
what is the definition of permanent dipole-permanent dipole attractions
attractions between the positive end of the dipole one one molecule and the negative end of the permanent dipole of a neighbouring molecule.
definition of VDW
attractions between the instantaneous and induced dipoles on neighbouring molecules
