periodicity 8

Question 1

periodic table

Answer 1

order of increasing atomic number

can predict the properties depending on its position

Question 2

groups

Answer 2

• the vertical column of elements
• similar chemical properties
• same number of electrons

Question 3

reactivity

Answer 3

s-block metals = get more reactive going down the group

transition metals = non-reactive

Question 4

periods

Answer 4

-horizontal rows

Question 5

placing hydrogen

Answer 5

-forms a 1+ ion but not chemically similar and is also a gas

Question 6

placing helium

Answer 6

-not a p-block element 1S2

Question 7

group 1,2,3 elements bonding

Answer 7

giant structure
ionic compounds
metallic bonding

Question 8

group 4 elements bonding

Answer 8

four covalent bonds (giant covalent)

Question 9

group 5,6,7 elements bonding

Answer 9

non-metals

covalent bonds

Question 10

group 0 (8) element bonding

Answer 10

noble gas
full outer shell
unreactive

Question 11

melting and boiling point

Answer 11

1 - group 4
2- group 3,2,1
3- group 6,5,7
4-group 8

Question 12

atomic radii

Answer 12

taken to be half the distance between the centres of a pair of atoms

Question 13

the size of the atom ……. going across a period

Answer 13

decrease

Question 14

radii of the atoms increase down a group

Answer 14

going down a group an extra shell of electrons are added, the electron is further away from the nucleus

Question 15

why does the first ionisation energy increase across a period

Answer 15

a number of protons in the nucleus increases but the electrons enter the same shell. so it gets increasing difficult to remove an electron

Question 16

why does the first ionisation energy decrease going down a group

Answer 16

the number of filled inner shells increase down the group, this means that there is an increase in shielding.
the electron is further away from the nucleus so it’s easier to remove

Question 17

why there is a drop in ionisation energy from one period to the next

Answer 17

the new main level starts and so there is an increase in atomic radius, the outer electron is further from the nucleus so less strongly attracted to its easier to remove

Question 18

drop in first ionisation energy between group 2 and 3

Answer 18

p-electron is already in a higher energy level than the s-electron, so it takes less energy to remove it

Question 19

drop in first ionisation energy between groups 5 and 6

Answer 19

an electron in a pair will be easier to remove that one in an orbital on its own because it is already being repealled by the other electron

Question 20

Bonding ( period 3)

Answer 20

Metallic - Na, Mg,Al
Giant covalent - Si
Covalent - P,S,Cl,Ar

Question 21

Structure ( period 3)

Answer 21

Giant metallic - Na,Mg,Al
Giant covalent - Si
Molecular - P4, S8, Cl2
Noble gas - Ar

Question 22

Atomic radii

Answer 22

Tells us the size of the atoms
Half the distance between the centres of a pair of atoms is used
Radius differs depending on what type of bonding
Decreases across a period ( theres a jump when starting the next period)

Question 23

Why the radii of atoms decrease across a period

Answer 23

Add a proton ( increase nuclear charge)
Increased charge pulls the electron in closer to the nucleus
No more shielding from next shells

Question 24

First ionisation energies

Answer 24

The enrgy required to convert 1 mole of gaseous ions into one mole of +1 gaseous ions

Question 25

first ionisation energy increases across a period

Answer 25

because more protons are added to the nucleus however no more shells are adding meaning there is no extra shielding. therefore it is harder to move an electron so the ionisation energy is more

Question 26

first ionisation energy drops as you go down a group

Answer 26

there is an increase in atomic radius and the outer electron is further away from the positive nucleus and so is easier to remove

Question 27

periodicity

Answer 27

the regular recurrence of the properties of elements when they are arranged in atomic number order as the periodic table

Question 28

classification

Answer 28

An element is classi ed as s, p, d or f block according to its position in the Periodic Table, which is determined by its proton number