Another major example of DATIVE HERE THE hydrogen atom has a
COVALENT BONDING- overalp
COVALENT BONDING is the formation small partial positive charge
between atomic orbitals, each
of Al2CL6 via 2 Al3cl3 molecules and the chlorine atom has a
containing one electron- creates
small partial negative charge
a shared pair of electrons
This separation of opposite
A COVALENT BOND IS THE
charge is called a DIPOLE
ELECTROSTATIC ATTRACTION
BETWEEN THE SHARED PAIR OF NOTE: POLAR BONDS DO NOT 1. Electrons in atoms are
ELECTRONS AND THE NUCLEI ALWAYS LEAD TO A POLAR constantly moving- at
OF THE BONDED ATOMS MOLECULE any moment, they may
- Lone pair of chlorine is given to 1 SHAPE OF MOLECCULES
be more electrons on
Bond length- internuclear aluminium atom If a molecule contains polar
BeCl2- linear BeCl3- triagonal planar one side of the atom
distance between two covalently covalent bonds and is
IONIC BONDING- electrostatic CH4- tetrahedral PCl5- triagonal bipyramidal than the other-
bonded atom- SHORTER BOND ASYMMETRICAL, it is a polar
attraction between opposite charged TEMPORARY DIPOLE
LENGTH STRONGER BONDING SF6- octahedral molecule
ions 2. This temporary dipole
this can be represented via dot ELECTRONEGATIVITY- the ability of an atom If molecules contain polar can induce an dipole in
WHAT FACTORS AFFECT THE to attract the bonding electrons in a covalent
and cross diagrams covalent bonds but is a neighbouring atom,
STRENGTH OF IONIC BONDING bond
SYMMETIRCAL, it will not be causing a weak
1) Ionic charge- the higher the ELECTRONEGAVITY INCREASES polar (non-polar) electrostatic attraction.
charge on the ions, the stronger ACROSS A PERIOD: 3. This induced dipole can
This is because the dipoles will
attraction between them further induce other
- Atomic raidus decreases cancel each other out, therefore dipoles in nearby
2) Ionic radius- The smaller the - Nucelar charge increases creating no net charge/ dipole
ionic radii, the closer the ions - Similar shielding effect particles
are in the lattice, strengthening - Stronger attraction between
nucleus and bonding pair of
WHAT AFFECTS THE
LONE PAIRS- these are electrons attraction between ions STRENGTH OF LONDON
electrons
found on the outer shell which FORCES
EVIDENCE OF EXSISTENCE OF IONS
are not involved in bonding
1. SIZE
BREAKING THE OCTET RULE (E.G
SF6)
Bonding and Structure - Molecular size
increases
POLAR IONIC BONDS - Bigger electron cloud
UP A GROUP: - Bigger temporary
If we apply an electric current to a EXAMPLE 1) Small, highly charged cation
dipole
sample containing colored ions, the As you go down have HIGH CHARGE DENSITY-
Predict the shape and bond angles in - Stronger London forces
ions should move to the opposite able to polarise negative ions
PCl3 molecule - Electron is further fo nucleus
charge (e.g b.p of Gp4 hydrides
- Atomic radius increases LARGER NEGATIVE IONS are
- Shielding effect increases
increases down group)
EXAMPLE- on a microscope slide and easier to polarise as their
- Weaker attraction between nucleus and bonding
silter paper, add a drop of CuCr2O7 ions electrons are further from the 2. POLARISABLITY=
DATIVE COVALENT BOND- this is pair of electrons
nucleus greater ability to distort
a covalent bond in which two Positive Blue copper ions move to the PURE COVALENT- little/no difference in electron cloud
atoms share a pair of electrons, negative side EXAMPLE: Magnesium bromide
electronegativity
both of being DONATED FROM PERMANENT DIPOLE -
Negative yellow dichromate ions move -Mg= small ionic raidus and high
ONE ATOM PURE IONIC- huge difference in electronegativity DIPOLE
to the positive charge= HIGH CHARGE
DENSITY - Electrostatic attraction
SHAPES OF MOLECULES
between partial
-Br- large molecules= easily
A shape of a molecules is determined positive and partial
polarisable so it can become
between the electron pairs that NOTE: the bonding pairs and lone negative end
distorted
surround the central atoms pairs and DETERMINED BY THE
POLAR COVALENT BOND- caused by difference
CENTRAL ATOMS (e.g P) - We can say that Magnesium
This is because electrons pairs REPEL in electronegativity
bromide has some COVALENT
Here we see that both electrons EACH OTHER- so they arrange EXAMPLE 2:
EXAMPLE: HCL CHARACTER.
are donated from the nitrogen themselves as far as possible
Predict the shape and bond angle(s)
atom to bond to the H+ atom INTERMOLECULAR FORCES
in H20
COVALENT BONDING- overalp
COVALENT BONDING is the formation small partial positive charge
between atomic orbitals, each
of Al2CL6 via 2 Al3cl3 molecules and the chlorine atom has a
containing one electron- creates
small partial negative charge
a shared pair of electrons
This separation of opposite
A COVALENT BOND IS THE
charge is called a DIPOLE
ELECTROSTATIC ATTRACTION
BETWEEN THE SHARED PAIR OF NOTE: POLAR BONDS DO NOT 1. Electrons in atoms are
ELECTRONS AND THE NUCLEI ALWAYS LEAD TO A POLAR constantly moving- at
OF THE BONDED ATOMS MOLECULE any moment, they may
- Lone pair of chlorine is given to 1 SHAPE OF MOLECCULES
be more electrons on
Bond length- internuclear aluminium atom If a molecule contains polar
BeCl2- linear BeCl3- triagonal planar one side of the atom
distance between two covalently covalent bonds and is
IONIC BONDING- electrostatic CH4- tetrahedral PCl5- triagonal bipyramidal than the other-
bonded atom- SHORTER BOND ASYMMETRICAL, it is a polar
attraction between opposite charged TEMPORARY DIPOLE
LENGTH STRONGER BONDING SF6- octahedral molecule
ions 2. This temporary dipole
this can be represented via dot ELECTRONEGATIVITY- the ability of an atom If molecules contain polar can induce an dipole in
WHAT FACTORS AFFECT THE to attract the bonding electrons in a covalent
and cross diagrams covalent bonds but is a neighbouring atom,
STRENGTH OF IONIC BONDING bond
SYMMETIRCAL, it will not be causing a weak
1) Ionic charge- the higher the ELECTRONEGAVITY INCREASES polar (non-polar) electrostatic attraction.
charge on the ions, the stronger ACROSS A PERIOD: 3. This induced dipole can
This is because the dipoles will
attraction between them further induce other
- Atomic raidus decreases cancel each other out, therefore dipoles in nearby
2) Ionic radius- The smaller the - Nucelar charge increases creating no net charge/ dipole
ionic radii, the closer the ions - Similar shielding effect particles
are in the lattice, strengthening - Stronger attraction between
nucleus and bonding pair of
WHAT AFFECTS THE
LONE PAIRS- these are electrons attraction between ions STRENGTH OF LONDON
electrons
found on the outer shell which FORCES
EVIDENCE OF EXSISTENCE OF IONS
are not involved in bonding
1. SIZE
BREAKING THE OCTET RULE (E.G
SF6)
Bonding and Structure - Molecular size
increases
POLAR IONIC BONDS - Bigger electron cloud
UP A GROUP: - Bigger temporary
If we apply an electric current to a EXAMPLE 1) Small, highly charged cation
dipole
sample containing colored ions, the As you go down have HIGH CHARGE DENSITY-
Predict the shape and bond angles in - Stronger London forces
ions should move to the opposite able to polarise negative ions
PCl3 molecule - Electron is further fo nucleus
charge (e.g b.p of Gp4 hydrides
- Atomic radius increases LARGER NEGATIVE IONS are
- Shielding effect increases
increases down group)
EXAMPLE- on a microscope slide and easier to polarise as their
- Weaker attraction between nucleus and bonding
silter paper, add a drop of CuCr2O7 ions electrons are further from the 2. POLARISABLITY=
DATIVE COVALENT BOND- this is pair of electrons
nucleus greater ability to distort
a covalent bond in which two Positive Blue copper ions move to the PURE COVALENT- little/no difference in electron cloud
atoms share a pair of electrons, negative side EXAMPLE: Magnesium bromide
electronegativity
both of being DONATED FROM PERMANENT DIPOLE -
Negative yellow dichromate ions move -Mg= small ionic raidus and high
ONE ATOM PURE IONIC- huge difference in electronegativity DIPOLE
to the positive charge= HIGH CHARGE
DENSITY - Electrostatic attraction
SHAPES OF MOLECULES
between partial
-Br- large molecules= easily
A shape of a molecules is determined positive and partial
polarisable so it can become
between the electron pairs that NOTE: the bonding pairs and lone negative end
distorted
surround the central atoms pairs and DETERMINED BY THE
POLAR COVALENT BOND- caused by difference
CENTRAL ATOMS (e.g P) - We can say that Magnesium
This is because electrons pairs REPEL in electronegativity
bromide has some COVALENT
Here we see that both electrons EACH OTHER- so they arrange EXAMPLE 2:
EXAMPLE: HCL CHARACTER.
are donated from the nitrogen themselves as far as possible
Predict the shape and bond angle(s)
atom to bond to the H+ atom INTERMOLECULAR FORCES
in H20
