network solids

Question 1

network solid examples

Answer 1

C (diamond), SiC (s), SiO2 (quartz)

Question 2

isoelectric

Answer 2

same number of electrons as nearest noble gas

Question 3

boron has an unfulfilled octet

Answer 3

happy with 6 valence electrons, forms more reactive and less stable bonds

Question 4

why does sulfur form an expanded octet

Answer 4

it uses a nearby d sub shell which allows for more room in its valence shells, expanded octets occur during 2p and beyond

Question 5

resonance structures

Answer 5

same formula, different lewis structures

Question 6

what is polarizability

Answer 6

tendency of an electron cloud to distort,

The larger the atomic or molecular polarizability, the greater the induced dipole moments, leading to stronger intermolecular forces and thus higher surface area interactions.

Question 7

Why is Bromine a liquid at room temperature

Answer 7

more electrons, more polarizable which means its bonds are harder to break preventing it from changing states

Question 8

why would the halogens have an increased melting and boiling point than the noble gases

Answer 8

because the halogens are diatomic

Question 9

what makes dissociation possible

Answer 9

ion-dipole forces

Question 10

properties of network covalent bonding

Answer 10

• hardness
• melting point
• solubility: insoluble in solvent because they are so large

NO INTERMOLECULAR FORCES IN NETWORK COVALENT BONDS

Question 11

viscosity

Answer 11

resistance of liquid to flow
increased viscosity with increased imf and decreased temperature

• larger molecule increases ldf strength and decreases the sliding around

Question 12

surface tension

Answer 12

h2o acts as if it has a “Skin” on it due to inward forces on surface, caused by hydrogen bonding

Question 13

cohesion and adhesion:

Answer 13

intermolecular forces that bind to similar molecules of one another are cohesive forces

intermolecular forces that bind a substance to a surface- adhesive

Question 14

what produce capillary action

Answer 14

adhesive forces, pulls h2o up a tube

Question 15

capillary action

Answer 15

• adhesive forces attract the liquid to the wall of the tube
• cohesive forces attract the liquid to itself
• h2o has stronger adhesive forces with glass whereas mercury has stronger cohesive forces with itself

Question 16

concave surface

Answer 16

• adhesive outweighs cohesive, where water molecules adhere to glass more than themselves

Question 17

convex surface

Answer 17

• cohesive outweighs adhesive, where mercury molecules collide with each other more than adhering to the wall

Question 18

phase changes

Answer 18

energy is either added or released

endothermic= adding temperature to break bonds, energy is absorbed, increased potential energy

exothermic= lowering temperature, releasing energy causing new bonds to form, decreased potential energy

Question 19

example of a phase change

Answer 19

• sweat pulls energy in the form of heat from your body as water (sweat) evaporates to make you feel cooler

Question 20

heat of fusion

heat of vapourization

heat of sublimation

Answer 20

fusion: energy required to change a solid at its melting point to a liquid

vapourization: energy requried to change a liquid at its boiling point to a gas

sublimation: energy required to change a solid directly to a gas

Question 21

melting point=

Answer 21

freezing point

Question 22

product of mass and heat of fusion

Answer 22

= heat

Question 23

emission spectrum

Answer 23

When an electric current passes through a gas, it gives energy to the gas. This energy is then given out as light of several definite wavelengths (colours).

Question 24

valence bond theory: how chemical bonds are formed by the overlap of orbitals

Answer 24

As they move closer and closer together, orbital overlap begins to occur, and a bond begins to form.