Physical: Bonding Flashcards
What are the three types of bonding?
ionic
metallic
covalent
Do ionic substances have high mp/bp?
yes, due to the strong electrostatic forces of attraction between oppositely charged ions acting in all directions so more energy is required to break the bonds
Do ionic substances conduct electricity?
when molten/in an aqueous solution
this is because the ions become free to move and carry charge
Are ionic substances strong?
yes, because the ionic bonds are strong and the ions are arranged in an ionic crystal lattice
Are ionic substances soluble?
yes, because the ions are attracted to the polar aspects of water
Do metallic substances have high mp/bp?
yes, due to the strong electrostatic forces of attraction between the delocalised electrons and the central positive metal ions in lattice
How does metallic bond strength increase?
greater the charge of the ion, the stronger the metallic bonds because the ion is stronger so the electrostatic attraction to the delocalised electrons is stronger so more energy is required to overcome the forces of attraction
Do metals conduct electricity?
yes, because the delocalised electrons are free to carry charge
Are metals soluble?
no, because there is no polar aspect to metallic substances
Do giant covalent substances have a high mp/bp?
MANY. STRONG covalent bonds between all atoms
Do giant covalent substances conduct electricity?
no because there are no free electrons or mobile ions carry charge
Do simple molecules have high mp/bp?
no. because intermolecular forces are weak between the molecules, so less energy is required to break the bonds so not a lot of energy is required to overcome the forces
What is covalent bonding?
the sharing of one or more PAIRs of electrons between non-metals
What is the A-level rule for covalent bonding?
central atoms can promote electrons between orbitals in the same principal energy level
but this promotion requires energy
How can you tell how many covalent bonds the central atom will make?
number of unpaired e⁻ = number of bonds that atom can make
What are lone pairs?
the unbonded pairs of e⁻ in the outer shell
Why are lone pairs more repulsive?
bonding pairs are stabilized between two atoms. Since there’s no atom on the other end of a lone pair, it spreads out more. So they repel more because the charge density is spread out more
What is the name of the molecule which has 2 bonding pairs and no lone pairs and its bond angle?
linear
180
What is the name of the molecule which has 3bp and no lp and its bond angle?
trigonal planar
120
What is the name of the molecule which has 2bp/1lp and its bond angle?
bent
117
What is the name of the molecule which has 4pb/0lp and its bond angle?
tetrahedral
109.5
What is the name of the molecule which has 3bp/1lp and its bond angle?
trigonal pyramidal
107
What is the name of the molecule which has 2pb/2lp/bond angle?
bent
104
What is the name of the molecule which has 5pb/bond angle?
trigonal bipyramidal
120 equatorial bonds (makes an equator)
90 axial bonds (face to or away from you)