Bonding (3.1.3)

Question 1

what does ionic bonding involve (giant ionic structure)?

Answer 1

many strong electrostatic forces of attraction going in all directions between oppositely charged ions in a lattice
(state ions if given compound)

Question 2

what does metallic bonding involve (giant metallic structure)?

Answer 2

strong electrostatic forces of attraction between positive ions and delocalised electrons arranged in a lattice

Question 3

what does the bonding in simple molecular structures involve?

Answer 3

strong covalent bonds between atoms in the molecule, but weak intermolecular forces of attraction between molecules

Question 4

what does a single covalent bond contain?

Answer 4

a shared pair of electrons

Question 5

what do multiple bonds contain?

Answer 5

multiple pairs of electrons

Question 6

what does a coordinate (dative covalent) bond contain?

Answer 6

a shared pair of electrons with both electrons supplied by one atom

Question 7

what is a lone pair of electrons?

Answer 7

when forming covalent bonds, a pair of electrons which aren’t involved in forming a bond

Question 8

what is a vacant orbital?

Answer 8

when forming covalent bonds, an orbital in the outer energy level of an atom which doesn’t contain any electrons

Question 9

draw the dot and cross diagram for AlCl3 and label the lone pairs of electrons/vacant orbital?

Answer 9

lone pairs on Cl atoms
vacant orbital on Al atom

Question 10

how is a covalent bond represented?

Answer 10

using a line

Question 11

how is a coordinate bond represented?

Answer 11

using an arrow

Question 12

draw a diagram to show what happens when NH3 and BCl3 react, and write the equation?

Answer 12

NH3 + BCl3 –> H3NBCl3

Question 13

draw a diagram to show what happens when Cl^- and AlCl3 react, and write the equation?

Answer 13

Cl^- + AlCl3 –> AlCl4^-

Question 14

what is electronegativity?

Answer 14

the ability of an atom to attract the pair of electrons (electron density) in a covalent bond towards itself

Question 15

what is the trend in electronegativity going across a period?

Answer 15

electronegativity values increase because the nuclear charge on the atoms increases but shielding is similar, so atoms attract the electrons more strongly

Question 16

what is the trend in electronegativity going down a group?

Answer 16

electronegativity values decrease because atoms have more energy levels and therefore more shielding, so atoms attract the electrons less strongly

Question 17

how is a polar covalent bond produced?

Answer 17

when electron distribution in a covalent bond between elements with different electronegativities is unsymmetrical

Question 18

which covalent bond is more polar and why - H-Cl and H-F?

Answer 18

H-F, because the bigger the difference in electronegativity between the atoms, the more the covalent bond is polar

Question 19

how can you show that a bond is polar?

Answer 19

using partial charges

Question 20

how do partial charges in a polar covalent bond work?

Answer 20

the atom with lower electronegativity has a positive partial charge (delta +) and the element with higher electronegativity has a negative partial charge (delta -)

Question 21

what can bonding pairs and lone pairs of electrons be described as?

Answer 21

charge clouds which repel each other

Question 22

what do pairs of electrons in the outer shells of atoms do?

Answer 22

they arrange themselves as far apart as possible to minimise repulsion

Question 23

what are the strengths of the repulsion between different types of bond?

Answer 23

strongest - lone pair-lone pair repulsion
lone pair-bond pair repulsion
weakest - bond pair-bond pair repulsion

Question 24

when drawing 3D shapes of molecules, what does a solid line mean?

Answer 24

atoms lie on the plane

Question 25

when drawing 3D shapes of molecules, what does a solid wedge mean?

Answer 25

the atom is coming out of the plane of the page

Question 26

when drawing 3D shapes of molecules, what does a dotted wedge mean?

Answer 26

the atom is projecting behind the plane of the page

Question 27

what is the effect of lone pairs of electrons on bond angles?

Answer 27

the lone pairs repel the bonding pairs more strongly, so the bond angle decreases as atoms are pushed further away (the more lone pairs, the stronger the repulsion)

Question 28

shape name and bond angles - 2 bps and no lps?

Answer 28

linear, 180 degrees

Question 29

shape name and bond angles - 3 bps and np lps?

Answer 29

trigonal planar, 120 degrees

Question 30

shape name and bond angles - 2 bps, 1 lp?

Answer 30

bent, 118 degrees

Question 31

shape name and bond angles - 4 bps, no lps?

Answer 31

tetrahedral, 109.5 degrees

Question 32

shape name and bond angles - 3 bps, 1 lp?

Answer 32

trigonal pyramidal, 107 degrees

Question 33

shape name and bond angles - 2 bps, 2 lps?

Answer 33

bent, 104.5 degrees

Question 34

shape name and bond angles - 5 bps, no lps

Answer 34

trigonal bipyramidal, 120 and 90 degrees

Question 35

shape name and bond angles - 4 bps, 1 lp?

Answer 35

seesaw, 90, 120 and 180 degrees

Question 36

shape name and bond angles - 3 bps, 2 lps?

Answer 36

t-shaped, 90 degrees

Question 37

shape name and bond angles - 2 bps, 3 lps?

Answer 37

linear, 180 degrees

Question 38

shape name and bond angles - 6 bps, no lps?

Answer 38

octahedral, 90 degrees

Question 39

shape name and bond angles - 5 bps, 1 lp?

Answer 39

square pyramidal, 90 degrees

Question 40

shape name and bond angles - 4 bps, 2 lps?

Answer 40

square planar, 90 degrees