1.6 bonding

Question 1

1a How do we know that ions exist?

Answer 1

physical properties of ionic compounds (brittle)
electron density maps
electrolysis

Question 2

1b How are ions formed?

Answer 2

electron loss or gain

Question 3

1d What is an ionic crystal on a molecular level?

Answer 3

a giant lattice of alternating ions

Question 4

1e What is an ionic bond?

Answer 4

electrostatic attraction between oppositely-charged ions

Question 5

1f Define ‘isoelectronic’.

Answer 5

same electronic structure

Question 6

1f What is the trend in ionic radii of isoelectronic ions?

eg N3- O2- F- Na+ Mg2+ Al3+

Answer 6

decreasing radius as nuclear charge increases (thereby pulling electrons in closer)

Question 7

1g How does an ionic lattice form?

Answer 7

metal loses electrons
non-metal gains electrons
ions are attracted to one another

Question 8

1i What is polarisation (of ions)?

Answer 8

electron imbalance from attraction to other nuclei, causing one end to be more negative than another

Question 9

1j Which two factors increase the polarising power of a cation?

Answer 9

radius (smaller radius, more polarising)
nuclear charge (greater charge, more polarising)

Question 10

1j Which factor increases the polarising power of an anion?

Answer 10

radius (larger radius, more polarisable)

Question 11

1k What does polarisation within ionic compounds lead to?

Answer 11

covalency (more polarised compounds are more covalent)

Question 12

1l How does the enthalpy of formation of MgCl2 prove that it is more stable than MgCl or MgCl3?

Answer 12

[waiting on answer from nmb]

Question 13

2a How is a covalent bond formed?

Answer 13

attraction between nuclei and shared pair(s) of electrons inbetween

Question 14

2ai How can we tell that covalent bonds are strong?

Answer 14

giant covalent structures (e.g. diamond) have high sublimation points

Question 15

2aii How do electron density maps prove the strength of covalent bonds?

Answer 15

buildup of electrons between nuclei - attraction

Question 16

2b What is a dative covalent bond?

Answer 16

a covalent bond wherein both of the electrons inbetween came from the same electron

Question 17

3a What do metals look like on a molecular level?

Answer 17

giant lattices of metal ions and delocalised electrons

Question 18

3b Describe metallic bonding.

Answer 18

attraction between metal ions and delocalised electrons