Chapter 7 - Periodicity (MODULE 3)

Question 1

How is the periodic table arranged

Answer 1

by atomic number

Question 2

how many periods and groups are in the periodic table

Answer 2

7 periods and 18 groups

Question 3

What is periodicity

Answer 3

repeating trends across the groups of each period

Question 4

What is the periodic trend of electron configuration

Answer 4

for each period, s- subshell filled then p- subshell

Question 5

What is the trend of electron configuration down a group

Answer 5

there is the same number of outer shell electrons for each element in a group

Question 6

Which groups are in the s-block

Answer 6

groups 1 and 2

Question 7

Which groups are in the p-block

Answer 7

groups 3,4,5,6,7,8

Question 8

What elements are in the d block

Answer 8

transition metals, groups 3-12

Question 9

What is first ionisation energy

Answer 9

the amount of energy required to remove one electron from each atom in one mole of gaseous atoms to form gaseous 1+ ions

Question 10

What three factors affect ionisation energy

Answer 10

atomic radius, nuclear charge and electron shielding

Question 11

how does atomic radius affect ionisation energy if all else is constant

Answer 11

greater atomic radius means less attraction and lower ionisation energy

Question 12

how does nuclear charge affect ionisation energy

Answer 12

more protons so greater attraction with greater nuclear charge

Question 13

how does electron shielding affect ionisation energy

Answer 13

inner shells repel outer shell electrons, reducing attraction and first ionisation energy

Question 14

how many ionisation energies does each atom have

Answer 14

as many as the number of electrons in an atom

Question 15

What is the second ionisation energy

Answer 15

the amount of energy required to remove one electron from each ion in one mole of gaseous 1+ ions to make gaseous 2+ ions

Question 16

How do successive ionisation energies compare for an element

Answer 16

always increasing, large jump when change in outer shell

Question 17

what can you tell from the successive ionisation energies of an atom

Answer 17

which group it is in

Question 18

What is the trend in first ionisation energies across a period

Answer 18

general increase across each period, sharp decrease to next period, slight decrease between subshells

Question 19

why does the first ionisation energy decrease down a group

Answer 19

greater shielding, less nuclear attraction, first ionisation energy decreases

Question 20

Why does the first ionisation energy increase across a period

Answer 20

same shielding, more nuclear charge, more energy required, greater first ionisation energy

Question 21

why is there a decrease in ionisation energy from Beryllium to Boron

Answer 21

2p subshell has greater energy level than 2s subshell, easier to remove electron

Question 22

Why is there a decrease in first ionisation energy from Nitrogen to Oxygen

Answer 22

paired electron orbital in Oxygen that repel each other. Therefore easier to lose electron and lower ionisation energy

Question 23

Where is the metal - non metal divide on the periodic table

Answer 23

top of group 13 to bottom off group 17

Question 24

What are the states of the metals at room temperature

Answer 24

mercury is liquid, rest are solid

Question 25

What is metallic bonding

Answer 25

electrostatic forces of attraction between positive metal ions and negative delocalised electrons

Question 26

Why can metals conduct electricity

Answer 26

delocalised electrons free to move and carry charge through the structure

Question 27

What structure do metals form when bonded

Answer 27

giant metallic lattices

Question 28

what are the two key properties of metals

Answer 28

high melting / boiling point and high electrical conductivity

Question 29

why do group 1 elements have the lowest average boiling points for metals

Answer 29

only form 1+ ions, weakest forces and so require least energy to break

Question 30

What does the melting point of metals depend on

Answer 30

the strength of the metallic bonds holding atoms together

Question 31

Why are metals insoluble

Answer 31

any interactions with water lead to reactions instead of dissolving

Question 32

what forces and bonds are present in simple covalent molecules

Answer 32

strong covalent bonds between atoms in a molecule, weak London forces between molecules

Question 33

What structure do elements such as boron, carbon and silicon have

Answer 33

giant covalent lattice

Question 34

Why do giant covalent structures have high melting and boiling points

Answer 34

lots of energy required to break strong covalent bonds between atoms

Question 35

Why do giant covalent structures have poor solubility

Answer 35

covalent bonds holding atoms together are too strong to be broken when interacting with solvents

Question 36

Why are graphite and graphene able to conduct electricity

Answer 36

each carbon only bonds to three others meaning there is one free electron able to move and carry charge through the structure

Question 37

What are the periodic trends of melting points in Periods 2 and 3

Answer 37

increasing through the giant structures. For simple molecules it depends on the number of electrons in the molecule: the more there are, the higher the boiling point. Noble gases have the lowest of the group

Question 38

Why do giant structures have higher melting points than simple molecules

Answer 38

giant structures contain strong covalent bonds which need lots of energy to break. Meanwhile simple molecules have weak intermolecular forces between molecules so have lower melting points