DN 6). Perid 3 And Group 2 Flashcards
Atomic radius across a period ….
Decreases
Why does Atomic radius across a period
Nuclear charge increases Outer electrons in same energy level Same shielding So attraction of electrons increase Atomic radius decreases
First ionisation across a period …
Increases
Why does First ionisation across a period
Nuclear charge increases
Outer electrons in same energy level same shielding and distance
Therefore more attraction
Graph shape of first ionisation energy across a period
Up 2 Down Up 3 Down Up 3
Melting point across a period
First 3 = metallic binding so as u go along the positive ion charge increases and more electrons in sea of delocalised electrons
Then spike as Si = macromolecular covalent
Then van dear waals = P4 , S8, Cl2, Ar
Atomic radius as you go down group 2
Increases
Why does atomic radius increase as you go down group 2
Outer electrons I a new energy level each time
First ionisation energy down group 2 explained
Despite increase in nuclear charge
Outer electrons further from nucleus
More shielding
First ionisation decreases
First ionisation energy down group 2
Decreases
Melting point as you go down group 2
Decreases
Why does melting point decrease down group 2
Metallic bonding
Nuclear charge always 2+
Electrons in sea of delocalised electrons further from nucleus
So weaker attraction so lowers
Reactivity if group 2
As down group reactivity increases
Measuring reactivity down group 2
Metal + 2 water –> m(OH)2 + hydrogen
White precipitate
More bubbles
Magnesium plus steam
Mg + H2O –> MgO + H2
Mg(OH)2
Milk of magnesium for indigestion
Ca(OH)2
Limewater as solution
Slaked lime as solid which reduces soil acidity
Ca and CaO
Flue gas disulphurisation
Flue gas disulphurisation equation
SO2 + 0.5 O2 + water —> H2SO4
Solubility if group 2 hydroxides
Get more soluble down
Group 2 sulphate so solubility
Get less soluble
Test for sulphites
Dilute HNO3
Barium chloride
White precipitate forms
Use for barium sulphate and a property
Barium meals for X-rays
It is insoluble
How to extract titanium
TiO2 + 2Cl2 +2C ----> TiCl4 + 2CO At 900 degrees TiCl4 + 2Mg ----> Ti + 2MgCl2 At 500 degrees Completed in an argon at,ops here to stop TiO2 reforming
