bonding Flashcards
what are the 3 main types of bonding?
covalent, ionic and metallic
what types of atom is ionic bonding between?
metal and non metal
what is ionic bonding?
the electrostatic force of attraction between oppositely charge ions
what structure do ionically bonded compounds form?
giant ionic lattice
what is an anion?
a negative ion
what is a cation?
a positive ion
what two factors affect the strength of ionic bonds?
size of the ions
charge of the ions
how does the size of an ion affect the strength of the ionic bond?
the smaller the ion, the stronger the attraction
how does the charge of ions affect the strength of the ionic bond?
the greater the charge difference, the stronger the ionic bond
what are the properties of ionic compounds?
conduct electricity
high melting point
suluble
why do ionic compounds conduct?
if MOLTEN OR DISSOLVED the ions are free to move and carry charge
why do ionic compounds have a high melting point?
strong electrostatic forces of attraction need a lot of energy to overcome
why are ionic compounds usually soluble in water?
water molecules pull ions away from the lattice causing it to dissolve
what type of atoms is covalent bonding between?
non metal + non metal
what is covalent bonding?
a shared pair of electrons
what is co-ordinate bonding?
when both the electrons come from the same species
the lone pair of electrons on an atom are donated
what is the shape of a molecular ion when it has 2 electron pairs?
linear
what is the bond angle of a linear molecule?
180
what is the shape of a molecular ion when it has 3 electron pairs?
trigonal planar
what is the bond angle of a trigonal planar molecule?
120
what is the shape of a molecular ion when it has 4 electron pairs?
tetrahedral
what is the bond angle of a tetrahedral molecule?
109.5
what is the shape of a molecular ion when it has 5 electron pairs?
trigonal bipyramidal
what are the bond angles of a trigonal bipyramidal molecule?
90 , 120
what is the shape of a molecular ion when it has 6 electron pairs?
octahedral
what is the bond angle of an octahedral molecule?
90
what is electronegativity?
the power of an atom to attract the electrons in a covalent bond
what factors affect electronegativity?
nuclear charge
atomic radius
shielding
how does nuclear charge affect electronegativity?
bigger charge = more attraction
how does atomic radius affect electronegativity?
smaller radius = more attraction
how does shielding affect electronegativity?
less shells = less shielding = more attraction
what are the trends in electronegativity in the periodic table?
increases ACROSS a period
increases UP a group
why does electronegativity decrease across a group?
- atomic structure increases so more shielding which means less attraction between nucleus and bonding pair
why does electronegativity increase across a period?
atomic radius decreases
more nuclear charge
so stronger attraction
what is a polar covalent bond?
covalent bond where the atoms are not shared equally
when does a polar bond happen?
when two atoms in a covalent bond have a different electronegativity
what are the three types of intermolecular forces?
van der waals
permanent dipole dipole
hydrogen bonding
