C3 Chemical Bonding

Question 1

electronegativity

Answer 1

power of an atom to attract electrons towards itself

Question 2

trend of electronegativity across Period

Answer 2

across period:
Nuclear charge increases, shielding effect remains constant, nuclear attraction to the electron becomes stronger, electronegativity INCREASES

Question 3

trend of electronegativity down Group

Answer 3

atomic radius increases, shielding effect increases, nuclear attraction to the electron becomes weaker, electronegativity DECREASES

Question 4

diff between ionic and covalent bond in terms of electronegativity

Answer 4

ionic bonds have a large diff of electronegativity between two bonding atoms

covalent bonds have a small diff of electronegativity between two bonding atoms

Question 5

ionic bonding

Answer 5

electrostatic attraction between oppositely charged ions

Question 6

metallic bonding

Answer 6

electrostatic attraction between lattice of positive ions and delocalised electrons

Question 7

why Mg has a higher m.p. than Na?

Answer 7

Mg has a greater no. of delocalised electrons than Na so Mg has a stronger metallic bond than Na.

Question 8

covalent bonding

Answer 8

electrostatic attraction between nuclei of two atoms to the shared pair of electrons

Question 9

coordinate/dative bonding

Answer 9

dative covalent bond is formed when an atom shares a pair of electrons directly to the other atom (from electronegative atom to electron deficient species)

Question 10

recall Al2Cl6 diagram

Answer 10

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Question 11

recall NH4+ diagram

Answer 11

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Question 12

bond energy

Answer 12

energy needed to break one mole of covalent bond between two atoms in the gaseous state

Question 13

Why does thermal stability decreases from H-F to H-I?

Answer 13

bond energy decreases from H-F to H-I, so less energy is required to break the covalent bond

Question 14

BOND ANGLES

Answer 14

2 bonding pairs: linear (180)
3 bonding pairs: trigonal planar (120)
2 bonding pairs, 1 lone pair: non-linear (118)
4 bonding pairs: tetrahedral (109.5)
3 bonding pairs, 1 lone pair: trigonal pyramidal (107)
2 bonding pairs, 2 lone pairs: non-linear (104.5)
5 bonding pairs: trigonal bipyramidal (90, 120)
6 bonding pairs: octahedral (90)

Question 15

bond polarity

Answer 15

phenomenon where the bonding pair of electrons in a covalent bond is not shared equally between two bonding atoms

Question 16

what are id-id forces affected by?

Answer 16

when the no. of electrons of the molecule increases, id-id forces become stronger

Question 17

what are pd-pd forces affected by?

Answer 17

when the polarity of the covalent bond increases, pd-pd forces become stronger

pd-pd forces are generally stronger than id-id forces

Question 18

recall how to draw hydrogen bond, along with the partial charges and lone pairs

Answer 18

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