topic 3 Flashcards
what is ionic bonding?
electrostatic force of attraction between oppositely charged ions
what are the properties of ionic compounds?
high melting and boiling point
hard but brittle
conduct electricity
soluble in polar solvents
how are ions formed?
it is formed when metals lose electrons
define lattice?
a 3d arrangement of particles forming and repeating a pattern only occuring in a crystal
define crystal?
solid that has well-defined edges and faces difracts x-rays and tends to have sharp melting points
What are the factors that affect ionic bond strength and how?
ionic charge = higher charge means stronger electrostatic attraction
ionic radius = smaller ions means stronger attraction
what is the trends in ionic radii?
down a group, the ionic radius increases. because more electron shells so weaker attraction
What is polarisation?
occurs when a cation distorts an anion electron cloud
what is covalent bonding?
strong electrostatic attraction between two nuclei and shared pair of electrons
what are the physical properties of covalent bonds?
high boiling and melting point
hardness
poor conductor of electricity
what are the physical properties of diamond?
it has very high melting point
it is very hard due to strong covalent bonds
doesnt conduct electricity
what are the physical properties of graphite?
has hexagonal rings arranged in layers
can conduct electricity
very high melting point
what does electronegitivity mean?
an atoms ability to attract a bonding pair of electrons in a covalent bond
what is the ionic covalent spectrum?
Bond Type Electronegativity Difference (ΔEN)
Pure Covalent 0
Polar Covalent 0.4 – 1.7
Ionic >1.7
how do you identify a polar bond?
A bond is polar if there is a difference in electronegativity between two atoms
How do you identify a polar molecule?
It has polar bonds.
The molecule is asymmetrical, so dipoles don’t cancel out.
What is the electron-electron repulsion theory?
1) electron pair repels each other
2)lone pairs repel more strongly
3)stronger repulsion = smaller bond angle
define bond length?
distance between the nuclei of two bonded atoms
define bond angle?
the angle btween two adjacent bonds in a molecule
what are the shapes of molecules and thier bond angles with an example?
for answer go to picture on computer
how much does a lone pair decrease the bond angle by?
2.5
What is metallic bonding?
strong electrostatic attraction between metal ions and delocalized electrons
why do metals have high melting point?
cause they have delocalised electrons and higher charge on the cations
What are the physical properties of metallic bonding?
high melting and boiling point
good conductor
mallable- layers of metal ions slide over eachother
