Group 2 Flashcards
Write an equation for the first ionization energy of magnesium
Mg-> Mg+ + e-
Explain the trend in ionization energies across period 3 on the periodic table
• First ionization energy increases across group 3 because:
• Of increased nuclear charge
• Decreased atomic radius
And same electron shielding which means more energy is needed to remove the first electron
However
• Dips at Al because outer electron is in a 3p orbital, higher energy than 3s orbital which means less energy needed to remove an electron
• Dips at S because one 3p orbital contains two electrons -> repulsion between paired electrons-> less energy needed to remove one
What happens to the first ionization energy as you go down 2 why?!
• Decreases because: number of filled electron shells increases down the group
• Increased shielding
• Increased atomic radius -> weaker force between outer electron and nucleus which means less energy needed to remove the electron
How does reactivity with water change as you go down group 2
• Increases
• Because outer electrons are further from the nucleus and more electron shielding so electrons are lost more easily
Give the equation for the reaction of barium and water
• Ba(s) + 2H2O(l) -> Ba(OH)2(aq) + H2(g)
Write an equation for the reaction of Magnesium and steam
Mg(s) + H2O(g) -> MgO(s) + H2(g)
What is the trend in hydroxide solubility down group 2
• Increases down the group
• Mg(OH)2 is almost insoluble
• Ba(OH)2 creates a strong alkaline solution
What is the trend in sulphate solubility down group 2
• Decreases down the group
• MgSO4 is soluble
• BaSO4 is insoluble
What is trend in melting point down group 2 and why?
• Decreases down the group
• Because sea of delocalized electrons is further from the positive charge of the nucleus
• Weaker metallic bonds/ forces of attraction which take less energy to weaken
What is the trend in atomic radius in group 2
• Increases as there are more occupied electron shells down the group
What are flue gases?
• Gases produced by power stations which are harmful to the environment
How can CaO or CaCO3 be used to remove flue gases? Write equations
• CaCO3(s) + SO2(g) -> CaSO3(s) + CO2 (g)
• CaO (s) + SO2 (g) -> CaSO3 (s)
What is Ca(OH)2 used for? Write an equation related to one of its uses
• Used to neutralize soil
• Ca(OH)2 (aq) + 2HCl (aq) -> 2H2O (l) + CaCl2 (aq)
• Used in agriculture to neutralize acid soil
What is Mg(OH)2 used for?
Milk of magnesia- antacid to treat digestion, heartburn, wind e.t.c
• Used in some indigestion tablets as an antacid
What is a use of BaSO4? Why is it safe?
• In barium meals to outline gut in x-rays
• Ba2+ is toxic but is fine as barium sulphate is insoluble
How can BaCl be used to test for sulphate ions
• Add to sample with HCl, white ppt will form if sulphate ions are present
• Ba2+ + SO4 2- -> BaSO4
What happens when group 2 elements react with water
• They are oxidized
• from a state of 0 to +2 forming M+ ions
Explain the solubility trends in Group 2
• They depend on the compound anion
• Compounds of Group 2 elements that only contain singly charged negative ions (OH-) increase in solubility down the group
• Compounds with doubly charged negative ions (SO42-) decrease in solubility down the group
What are Group 3 compounds mostly used for?
Neutralizing acids
Give the equation of neutralization
H+ + OH- -> H2O
Write out the test for sulfate ions
• Ba2+ (aq) + SO42-(aq) -> BaSO4(s)
• BaCl2(aq) + FeSO4(aq)-> BaSO4(s) + FeCl2(aq)
What is an antacid?
A substance that neutralizes excess stomach acid
How does barium sulfate in barium meals work?
• Barium Sulfate is opaque to X-rays, they won’t pass through it.
• A patient swallows barium meal which is a suspension of barium sulfate.
• The barium sulfate coats the tissues, making them show up on the X-rays, showing the structure of the organs
Describe how magnesium is used in the extraction of titanium
• The main titanium ore, titanium(IV) oxide (TiO2) is first converted to titanium(IV) chloride (TiCl4) by heating it with carbon in a steam of chlorine gas.
• The titanium chloride is then purified by fractional distillation, before being reduced by magnesium in a furnace at almost 1000*C