2.2.2 bonding and structure

Question 1

what is ionic bonding

Answer 1

electrostatic attraction between oppositely charged ions

Question 2

can ionic compounds dissolve in water and why

Answer 2

yes-as water molecules are polar so they attract the positive and negative charges

Question 3

can ionic compounds conduct electricity and why

Answer 3

yes when molten as the IONS are free to move
no when solid as the IONS are in fixed positions and cannot move

Question 4

what is the melting/boiling point of ionic compounds

Answer 4

high melting point as there’s a strong electrostatic attraction between oppositely charged ions

Question 5

what is a covalent bond

Answer 5

electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms

Question 6

what is a dative covalent bond AKA

Answer 6

co ordinate bond

Question 7

what is a dative covalent bond

Answer 7

when one atom donates a pair of electrons to form a bond
eg-NH4

Question 8

how can a dative covalent bond be represented

Answer 8

using an arrow

Question 9

shape + bond angle + draw
2 BP and 0LP

Answer 9

linear
180

Question 10

shape + bond angle + draw
3 BP and 0LP

Answer 10

Trigonal planar
120

Question 11

shape + bond angle + draw
3 BP and 1LP

Answer 11

Trigonal pyramidal
107

Question 12

shape + bond angle + draw
4BP and 0LP

Answer 12

tetrahedral
109.5

Question 13

shape + bond angle + draw
2BP and 2LP

Answer 13

bent/non-linear
104.5

Question 14

shape + bond angle + draw
6BP and 0LP

Answer 14

octahedral
90

Question 15

what is electronegativity

Answer 15

ability of an atom to attract a bonded pair of electrons towards itself in a covalent bond

Question 16

how does electronegativity change across a period

Answer 16

it increases

Question 17

how does electronegativity change down a group

Answer 17

it decreases

Question 18

what is the most electronegative element

Answer 18

flourine>oxygen>nitrogen

Question 19

what are the three factors that electronegativity depends on

Answer 19

-atomic radius
-electron shielding
-protons in nucleus

Question 20

what is a pure covalent bond + eg

Answer 20

both atoms have same or similar electronegativity
eg-C-H
Cl-Cl

Question 21

what is a polar covalent bond

Answer 21

small difference in electronegativity between the atoms

Question 22

what is an ionic bond

Answer 22

large difference in electronegativity

Question 23

how can you distinguish a polar bond

Answer 23

-no symmetry
-overall dipoles don’t cancel

Question 24

how can you distinguish a non-polar bond

Answer 24

-symmetrical
-overall dipoles cancel

Question 25

how does a temporary dipole arise

Answer 25

-uneven distribution of electrons -causes a temporary dipole -this induces a dipole in a neighbouring molecule

Question 26

where are induced dipole-dipole forces found

Answer 26

simple covalent lattice weak London forces between molecules

Question 27

where are covalent bonds found

Answer 27

giant covalent lattice strong covalent bonds between atoms

Question 28

what is hydrogen bonding

Answer 28

Hydrogen is covalently bonded to fluorine, oxygen and nitrogen

Question 29

what should you include when drawing hydrogen bonds

Answer 29

delta positive and delta negative lone pairs of electrons **make sure you label the hydrogen bond**

Question 30

what are the two anomalous properties of water explained

Answer 30

Property 1 Ice is less dense than water Explanation 1 The molecules in ice are held apart by hydrogen bonds OR ice has an open lattice OR structure Property 2 Ice has a relatively high melting point Explanation 2 Hydrogen bonds are relatively strong OR Hydrogen bonds are stronger (than other intermolecular attractions or forces) OR More energy is needed to overcome hydrogen bonding