Module 3 Flashcards
definition of ionisation energies
- Energy required to remove 1e- from each atom in 1 mole of gaseous atoms to form 1 mole of gaseous ions.
What would be the equation of the first ionisation equation for oxygen?
O (g) → O+ (g) + e-
What are the factors affecting ionisation energies?
1) charge of nucleus
Increase of charge = increase in ionisation energies
2) distance from nucleus
Increase in distance = decrease in ionisation energies
3) election shielding
Increase in shielding = decrease in ionisation energies
Why does I.E. Increase throughout periods?
increase in nuclear charge having greater pull on electrons therefore more energy required to remove electrons.
Why does I.E. Decrease down the group?
Increase in distance from nucleus, therefore increase in shielding
Definition of second ionisation energy
the energy needed to remove 1 electron from each ion of an element in 1 mole of gaseous +1 ions to form 1 mole of gaseous ions with a +2 charge
Trends of going down a group
- Atomic radius increases
- more inner shells so shielding increases
- nuclear attraction on outer elections decreases
- first ionisation energy decreases
Trend in first ionisation energy across a period
- Nuclear charge increases
- same shell: similar shielding
- nuclear attraction increases
- Atomic radius decreases
- first ionisation energy increases
Why does first ionisation energy decrease between group 2 and 3?
Decrease between 2 to 3 because in group 3 the outermost electrons are in p orbitals whereas in group 2 they’re in s orbitals, so the electrons are easier to be removed
Does first ionisation increase or decrease down a group? Why?
Decrease
Shielding increases - weaker attraction
Atomic radius increases -distance between the outer electrons and nucleus increases - weaker attraction
Increase in number of protons is outweighed by increase in distance and shielding
Properties of giant metallic lattices?
High melting and boiling point
Good electrical conductors
Malleability
Ductility
What is ductile metal?
The metal can be made stretched (e.g can be made into wires)
What is malleable metal mean?
The metal can be shaped into different forms
Common name for group 2 metals?
Alkaline earth metals
Most reactive group 2 metal?
Barium
3 physical properties of group 2 metals
-High melting and boiling points
-low density metals
-form colourless compounds
What happens to the first ionisation energy as you go down ground 2? Why?
Decreases because :
-number of filled electron shells increases down the group, increased shielding
-increased atomic radius, weaker force
-electron and nucleus, less energy needed to remove electron
Write an equation for the reaction of calcium and oxygen
2 Ca (s) + O2 (g) —> 2CaO (s)
What products when group 2 elements react with water?
Hydroxide and hydrogen gas
Which group 2 element doesn’t react with water?
Beryllium
Which group 2 element reacts slowly with water?
Magnesium
What type of reaction is the reaction between group 2 metal and water?
Redox reaction
Write an equation for the reaction between barium and water
Ba (s) + 2H2O —> Ba(OH)2 (aq) + H2 (g)
What is oxidised and what is reduced in a reaction between group 2 metal and water?
Metal = oxidised
One hydrogen atom from each water = reduced
