periodicity

Question 1

What were elements ordered in before

Answer 1

Atomic mass

Question 2

What did Dobereiner do

Answer 2

Grouped elements according to their characteristics

He grouped elements into 3 (triads)

Question 3

What did Newland do

Answer 3

Grouped elements in order of mass
Noticed every 8th element had similar properties
(octaves)

Question 4

What did Mendeleev do

Answer 4

Still ordered elements in atomic mass
Left gaps where elements didn’t fit newlands theory
Elements grouped in similar chemical properties

Question 5

Ionisation energy meaning

Answer 5

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

Question 6

What does ionisation energy depend on

Answer 6

Shielding
Nuclear charge - The more protons in the nucleus the bigger the attraction between the nucleus and outer electrons.
Atomic size - the bigger the atom the further away from the outer electron from the nucleus. Attractive force reduces.

Question 7

What happens to ionisation energy as we go across the period

Answer 7

Increasing no of protons
Increases nuclear attraction
Shielding is similar

Question 8

Orbital order in the periodic table

Answer 8

s,d,p,f

Question 9

What happens as you go across the period to the atomic radii..

Answer 9

atomic radius decreases
Increased nuclear charge as there is an increase in protons
This pulls the outer shell of electrons further in towards the electrons.

Question 10

what happens to the atomic radius as you go down group.

Answer 10

Increases due to extra electron shells added to each element.

Question 11

What happens to the melting point as the charge of metals increases

Answer 11

Have an increasing positive charge
An increasing number of delocalised electrons and smaller ionic radius
Increased electrostatic attraction
Leading to a stronger metallic bond
Increasing melting bond.