Periodicity

Question 1

who credited the periodic table today and how was it structured

Answer 1

ordered it by atomic mass but left gaps where elements didn’t fit Newlands theory
elements now grouped in terms of similar chemical properties

Question 2

how is the modern periodic table grouped

Answer 2

by proton number
same group has similar properties
periods are rows and columns are group
elements in same period have same number of electron numbers

Question 3

how is the periodic table grouped into s,p,d and f block

Answer 3

left side s block
middle is d block
right id b block
bottom is f block

Question 4

what is ionisation energy

Answer 4

minimum amount of energy required to remove 1 mole of electrons from 1 mole of atoms in the gaseous state

Question 5

how does shielding affect ionisation energy

Answer 5

the more electron shells between positive nucleus and negative electron being removed the less energy is required

Question 6

how does nuclear charge affect ionisation energy

Answer 6

the more protons in the nucleus the bigger the attraction between nucleus and outer electrons, more energy to remove the electron

Question 7

ionisation requires energy therefore they are always

Answer 7

endothermic and have a positive value

Question 8

ionisation energy _____as we go down a group

Answer 8

decreases

Question 9

why does ionisation energy decrease as we go down a group

Answer 9

atomic radius increases
attractive force is weaker
energy required decreases
shielding increases

Question 10

ionisation energy ___ as we go across a period

Answer 10

increases

Question 11

why does ionisation energy increase as we go across a period

Answer 11

increasing number of protons
nuclear attraction increases
shielding is similar
more energy required to remove outermost electron

Question 12

how does aluminium provide evidence for sub shells

Answer 12

the outermost electron sits in a higher energy sub-shell slightly higher energy sub shell which is further from the nucleus

Question 13

how is sulphur evidence for electron repulsion in an orbital

Answer 13

phosphorus and sulfur both have outer electrons in the 3p orbital so shielding is the same
removing electron from sulfur involves taking it from an orbital with two electrons
electrons repel each other so less energy needed remove electron from orbital with two electrons than one

Question 14

what is successive ionisation

Answer 14

when more than one electron is removed from the same atom

Question 15

what are two examples of giant covalent structures

Answer 15

graphite and diamond

Question 16

describe the structure of graphite and its features

Answer 16

each carbon bonded three times, 4th electron is delocalised
layers slide as weak forces between layers
delocalised electrons allow conduction of electricity
strong covalent bonds mean high melting point
insoluble

Question 17

describe the structure and function of diamond and its properties

Answer 17

each carbon bonded four times
tightly packed so can conduct heat
high melting point due to strong covalent bonds
doesn’t conduct electricity
insoluble

Question 18

what substance is diamond similar to

Answer 18

silicon

Question 19

what bonding is present in metals

Answer 19

giant metallic lattice

Question 20

what is the structure and properties of graphene

Answer 20

1 layer of graphite
made up of hexagonal carbon rings
delocalised, free moving electrons which strengthen covalent bonds and allow conduction of electricity
transparent and light

Question 21

what is the use of graphene

Answer 21

aircraft shells
super computers
smart phone screens

Question 22

describe metallic bonding and how this gives metals their property

Answer 22

positive metal ions amongst sea of delocalised electrons
electrostatic attraction between positive metal ions and negative delocalised electrons
the more electrons the higher the melting point
good thermal conductors
high melting points
good electrical conductors
insoluble as metallic bonds are strong

Question 23

how does melting point change across a period

Answer 23

increase as metals have increasing positive charge
increasing number of delocalised electrons
smaller ionic radius so stronger metallic bond