bonding

Question 1

ionic bonding

Answer 1

electrostatic forces of attraction between oppositely charged ions in a lattice.

Question 2

ionic lattice

Answer 2

each ion is surrounded by oppositely charged ions. They are held in place by electrostatic forces of attraction. However, the ionic model assumes all ions to be perfectly spherical.

Question 3

ionic properties

Answer 3

High melting point due to strong electrostatic forces of attraction between oppositely charged ions which requires lots of energy to break. Can only conduct when molten or dissolved in water. As a solid, the ions are in fixed positions but when molten, the bonds break and the ions are free to move and carry charge. Some ionic compounds can dissolve as the slightly positive hydrogen atoms are attracted to the anions while slightly negative oxygen atoms are attracted to the cations.

Question 4

ammonium ion formula

Answer 4

NH4^+

Question 5

hydroxide ion formula

Answer 5

OH^-

Question 6

sulfate ion formula

Answer 6

SO4^2-

Question 7

carbonate ion formula

Answer 7

CO3^2-

Question 8

nitrate ion formula

Answer 8

NO3^-

Question 9

hydrogen carbonate ion formula

Answer 9

HCO3^-

Question 10

covalent bonding

Answer 10

electrostatic attraction between the shared electrons and the two positive nuclei of non-metals

Question 11

dative/coordinate bond

Answer 11

a shared pair of electrons supplied by one atom. represented by an arrow.

Question 12

simple covalent molecules

Answer 12

low m.p and b.p because they have weak intermolecular forces of attraction that are easy to overcome. therefore, they are gases at room temperature. the cannot conduct electricity as they have no free electricity.

Question 13

compare diamond and graphite

Answer 13

both are giant covalent structures that have high m.p. because there are lots of strong covalent bonds holding the carbon atoms together. diamond is hard because it is a lattice structure held by very strong covalent bonds. Graphite is softer as it is arranged in layers that can slide over each other. The carbon atoms in diamond form 4 bonds while in graphite, it can only form 3. Therefore, it can conduct electricity as it has delocalised electrons.

Question 14

metallic bonding

Answer 14

the electrostatic force of attraction between the positively charged metal ions and the negatively charged sea of delocalised electrons. Atoms contribute their outer shell electrons to the sea of delocalised electrons.

Question 15

properties of metals

Answer 15

metal atoms are held together by strong electrostatic forces of attraction that require lots of energy to break so their m.p is high. they conduct electricity because they have a sea of delocalised electrons that are free to move and carry charge. they are malleable because the atoms are arranged in layers that can easily slide over eachother.

Question 16

factors affecting metallic bond strength

Answer 16

charge of ion
number of delocalised electrons
size of ion

Question 17

trigonal pyramidal

Answer 17

3 bonding pairs
1 lone pair
bond angle 107

Question 18

bent

Answer 18

2 bonding pairs
2 lone pairs
bond angle 104.5

Question 19

trigonal bipyramidal

Answer 19

5 bonding pairs
0 lone pairs
bond angle 120 and 90

Question 20

t-shaped

Answer 20

3 bonding pairs
2 lone pairs
bond angle 88

Question 21

octahedral

Answer 21

6 bonding pairs
0 lone pairs
bond angle 90

Question 22

trigonal planar

Answer 22

3 bonding pairs
0 lone pairs
bond angle 120

Question 23

seesaw

Answer 23

4 bonding pairs
1 lone pair
bond angle 87 and 102

Question 24

square planar

Answer 24

4 bonding pairs
2 lone pairs
bond angle 90

Question 25

tetrahedral

Answer 25

4 bonding pairs
0 lone pairs
bond angle 109.5

Question 26

linear

Answer 26

2 bonding pairs
0 lone pairs
bond angle 180

Question 27

working out shape of H20

Answer 27

central atom= oxygen
O= group 6
bonded to 2 hydrogens
6+2/2= 4 pairs
4-2=2
2 b.p 2 l.p

Question 28

electronegativity

Answer 28

the power of an atom to attract a pair of electrons in a covalent bond

Question 29

factors affecting electronegativity

Answer 29

nuclear charge- more protons means stronger attraction between the nucleus and bonding pair of electrons (greater nuclear charge = greater electronegativity)
atomic radius - the closer to the nucleus, the stronger the attraction between the nucleus and bonding pairs of electrons. (smaller atomic radius = greater electronegativity)
shielding - less electron shells between the nucleus and electrons = less shielding so stronger attraction between nucleus and bonding pair of electrons