3.1.1 Periodicity

Question 1

what is periodicity?

Answer 1

repeating trends of physical or chemical properties

Question 2

what are periods?

Answer 2

horizontal rows of elements

Question 3

what are groups?

Answer 3

vertical rows of elements

Question 4

where is the s block located on the periodic tables?

Answer 4

left

Question 5

where is the p block located on the periodic tables?

Answer 5

right

Question 6

where is the d block located on the periodic tables?

Answer 6

middle

Question 7

what puts each element in the blocks?

Answer 7

outermost electron in each subshell

Question 8

Atomic radius increases down a group (3 points)

Answer 8

> increase in no of shells
increase in shielding
outer electron is further from the nucleus

Question 9

Atomic radius decreases down a group (3 points)

Answer 9

> no of protons increases
shielding is constant/ same
electrons are more strongly attracted to the nucleus and atomic radius decreases

Question 10

what is the first ionisation energy?

Answer 10

the energy required to remove 1 mol of electrons from 1 mol of gaseous atoms

Question 11

trend in the 1st ionisation energy down the group (5 points)

Answer 11

> ionisation energy decreases
increase in shells
more shielding
weaker attraction between nucleus and outer electron
less energy required to removed electron

Question 12

Explain why first IE of Al(G3) is less that that of Mg (G2)? s to p block (3 points)

Answer 12

> IE decreases
electron is removed from a higher energy p subshell
weaker attraction between nucleus and outer electron

Question 13

trend in the 1st ionisation energy across the periods (4 points)

Answer 13

across periods is an increase in IE
> IE increases
> no of protons increase
> shielding is constant
> stronger attraction between nucleus and outer electron

Question 14

Explain why first IE of S(G6) is less that that of P(G5)? pair of sticks p3 to p4 (3 points)

Answer 14

> IE Decreases
there is a pair of electrons in p orbital
extra repulsion means less energy is required to remove the electron

Question 15

Question 16

Why is the first ionisation energy of beryllium greater than magnesium?(2 points)

Answer 16

> beryllium has less shells
stronger attraction between the outer electron and nucleus

Question 17

Why is the first ionisation energy of strontium less than calcium?(3 points)

Answer 17

> strontium has more shells that calcium
weaker attraction between outer electron and nucleus
more shielding

Question 18

Why is the first ionisation energy of magnesium greater than sodium? (3 points)

Answer 18

> Mg has more protons
same no of shells/ same shielding
stronger attraction between outer electron and nucleus

Question 19

Why is the first ionisation energy of boron less than Be?(2 points)

Answer 19

> weaker attraction between the outer electron and nucleus
electron from boron is removed from the higher energy p subshell

Question 20

Why is the first ionisation energy of oxygen less than nitrogen?(2 points)

Answer 20

> O- pair of electrons in p orbital
extra repulsion - less energy is needed to remove the electron

Question 21

Why is the first ionisation energy of arsenic greater than selenium?(2 points)

Answer 21

> Se- pair of electrons in p orbital
extra repulsion - less energy is needed to remove the electron in Se

Question 22

why does successive IEs always increase? (4 points)

Answer 22

> positive charge on the ion increases
ionic radius decreases
nuclear attraction on the outer electron increases
shielding is constant

Question 23

what is metallic bonding?

Answer 23

strong electrostatic attraction between positive ions and delocalised electron

Question 24

draw metallic bonding

Answer 24

Question 25

what are the three main factors that affect the strength of metallic bonding?

Answer 25

1. Number of protons/ Strength of nuclear attraction. >The more protons the stronger the bond 2. Number of delocalised electrons per atom >(the outer shell electrons are delocalised) The more delocalised electrons the stronger the bond 3. Size of ion. >The smaller the ion, the stronger the bond.

Question 26

Factors that affect Ionisation energy (3)

Answer 26

1.The attraction of the nucleus > (The more protons in the nucleus the greater the attraction) 2. The distance of the electrons from the nucleus > (The bigger the atom the further the outer electrons are from the nucleus and the weaker the attraction to the nucleus) 3. Shielding of the attraction of the nucleus > (An electron in an outer shell is repelled by electrons in complete inner shells, weakening the attraction of the nucleus)

Question 27

giant covalent structure silicon > bonding > conduct electricity? > bp/ mp?

Answer 27

> each silicon atom bonded to 4 other silicon atoms > strong covalent bonds require a lot of energy to break > no as there is no delocalised electrons > high the strong covalent bonds between atoms require a lot of energy to break

Question 28

giant covalent structure graphene (carbon) > bonding > conduct electricity? > bp/ mp?

Answer 28

> each carbon atom bonded to 3 other carbon atoms forming a hexagonal layer > strong covalent bonds require a lot of energy to break > high the strong covalent bonds between atoms require a lot of energy to break

Question 29

giant covalent structure graphite (carbon) > bonding > conduct electricity? > bp/ mp?

Answer 29

> each carbon atom bonded to 3 other carbon atoms forming a hexagonal layer > strong covalent bonds require a lot of energy to break >weak London forces between layers > high the strong covalent bonds between atoms require a lot of energy to break

Question 30

giant covalent structure diamond (carbon) > bonding > conduct electricity? > bp/ mp?

Answer 30

> each carbon atom bonded to 4 other carbon atoms > strong covalent bonds require a lot of energy to break > no as there is no delocalised electrons > high the strong covalent bonds between atoms require a lot of energy to break

Question 31

giant metallic lattice > period 2 elements > period 3 elements > melting/ boiling points

Answer 31

> Li, Be > Na, Mg, Al > high mp and bp due to strong electrostatic attraction between positive ions and delocalised electrons

Question 32

giant covalent > period 2 elements > period 3 elements > melting/ boiling points

Answer 32

> C > Si > very high mp and bp due to strong covalent bonds which require a lot of energy to break

Question 33

simple molecular > period 2 elements > period 3 elements > melting/ boiling points

Answer 33

> N2, F2, O2, Ne > P4, Cl2, S8, Ar > low mp and bp as have weak London forces between molecules which require less energy to break

Question 34

why is Ar and Ne monoatomic?

Answer 34

weak london forces between atoms

Question 35

which ones got a higher first ionisation energy and why? lithium or sodium

Answer 35

lithium > less shielding > less shells > stronger attraction between nucleus and outer electron

Question 36

which ones got a higher first ionisation energy and why? aluminium or silicon

Answer 36

silicon > same no of shells > same shielding > increase in protons > stronger attraction between nucleus and outer electron

Question 37

which ones got a higher first ionisation energy and why? calcium or gallium

Answer 37

calcium > gallium outer electron removed from high energy p sub shell > gallium has a weaker attraction between nucleus and outer electron

Question 38

describe and explain the trend in melting and boiling points of the period 3 metals

Answer 38

• increases • charges increase • size of ion decreases and no of electrons • steonger metallic bonds increase due to stronger electrostatic forces of attraction between postitive ions and delocalised electrons

Question 39

why does silicon have a very high melting and boiling point?

Answer 39

• strong covalent bonding between atoms require a lot of energy to break • giant covalent structure

Question 40

explain the trend in melting and boiling point of the simple molecular substances in period 3

Answer 40

• IDD forces increase with size of molecule and more electrons • mp and bp decrease in order S8>P4>Cl2>Ar

Question 41

why does sodium have a higher melting point than ammonia? • give the structure type •name type of attraction being broken and relative strength • compare melting points

Answer 41

• sodium oxide forms a giant ionic lattice, ammonia forms a simple molecular structure • sodium oxide has strong electrostatic forces of attraction between oppositely charged ions • the strongest intermolecular forces between ammonia molecules are hydrogen bonds • ionic bonds are stronger than hydrogen bonds so required more energy to overcome the attractions

Question 42

explain why the boiling points of fluorine and hydrogen fluoride are - 188°c and 19.5°c • give the structure type •name type of attraction being broken and relative strength • compare melting points

Answer 42

• fluorine and hydrogen fluoride form a simple molecular structure • the strongest IMD forces between hydrogen molecules are hydrogen bonds • the strongest IMD forces between fluorine are PDD forces • hydrogen bonds are stronger than PDD forces so requre more energy to break

Question 43

metallic bonding is the strong ... forces of attraction between positive metal ions and a sea of ... electrons.

Answer 43

> electrostatic > delocalised

Question 44

sodium, magnesium and aluminium all form ... ... ... structures

Answer 44

giant metallic lattice

Question 45

the boiling points increases from ... to ... because the ... increases, the size ... and the strength of the metallic bond increases.

Answer 45

> sodium > aluminium > charge > decreases

Question 46

silicon is a .... ..... substance with strong ... bonds extended throughout

Answer 46

giant covalent covalent

Question 47

phosphorus, sulfur, chlorine and argan form simple molecular structures, and have ... forces between the molecules

Answer 47

london

Question 48

sulfur exists as an S8 molecule so has the ... amount of london forces between the molecules so has the ... melting/boiling point.

Answer 48

highest greatest