Bonding and Structure

Question 1

why does a giant lattice have a high melting/boiling point?

Answer 1

• lots of strong bonds to break, takes a lot of energy to overcome
• strong electrostatic attractions between oppositely charges ions

Question 2

when are ionic bonds formed?

Answer 2

metal and non metal reacts

Question 3

when are covalent bonds formed?

Answer 3

two non metals react

Question 4

what are graphite’s properties and why?

Answer 4

• high melting point, strong and many covalent bonds
• insoluble in water
• soft, giant layers weak bonds between so can slide
• conducts electricity, each C atom makes only 3 bonds, so one free C atom to move freely and carry charge (delocalised electrons)

Question 5

why can diamond not conduct electricity? (as well as most other covalently bonded substances)

Answer 5

all atoms have no free electrons as all outer shell electrons are involved in covalent bonding

Question 6

do simple covalent molecules conduct electricity?

Answer 6

no, they have no overall charge, so cannot carry charge (no conduct)

Question 7

what type of arrangement are ions in (in ionicly bonded substances) ?

Answer 7

a giant lattice

Question 8

do simple covalent molecules have a low/high boiling point and why?

Answer 8

low, the covalent bonds are strong BUUT there are weak intermolecular forces between each molecule which don’t take a lot of energy to overcome

Question 9

why do giant covalent structures have a high melting point?

Answer 9

many strong covalent bonds, difficult to overcome (especially diamond, each C atom forms 4 strong covalent bonds)

Question 10

what is nanoscience?

Answer 10

the science of tiny things, more specifically, structures between 1-100nm in size

Question 11

what are some advantages of nono particles?

Answer 11

• very small, large surface area to volume ratio, very reactive, can be used as catalyst
• many novel and exciting applications

Question 12

3 uses of nano particles (ns if needed???)

Answer 12

• titanium oxide on windows, sun, dirt, reaction

- titanium oxide and zinc oxide, sun cream, more effective, UV rays

Question 13

what are some risks/disadvantages of nano particles?

Answer 13

• expensive
• high reactivity is dangerous
• unpredictable effects from breathing in (lungs then into bloodstream)

Question 14

what is a covalent bond? (how ish)

Answer 14

non metals reacting together to share pairs of electrons to form molecules

Question 15

Do ionic compounds conduct electricity?

Answer 15

only when dissolved in water or is molten, ions are free to move, instead of just vibrating on the spot so electrons can move freely through the structure

Question 16

do ionic compounds dissolve in water?

Answer 16

yes