Group 2

Created by

Khads <3

Cards (18)

What are the group 2 metals called and why?
+ alkaline earth metals
+ name comes from the alkaline properties of group 2 metal hydroxides
How are group 2 metals normally found?
+ do not occur in elemental form naturally
+ found in stable compounds on earth such as CaCO3
Why are group 2 metals reducing agents? 
+ each element has two more electrons than the noble gas electronic configuration
+ two electrons in outer s-subshell
+ redox are the most common reactions of group 2 elements
+ each metal atom is oxidised -> loses 2 electrons to form 2+ ion
+ another species gains the two electrons and is reduced -> group 2 is reducing agents
How does magnesium burn in oxygen?
with a brilliant white light
How do Group 2 elements react with water?
+ form alkaline hydroxide bases M(OH)2 and hydrogen gas
+ reactivity increases with water down the group and Beryllium has no reaction
+ magnesium reacts slowly with cold water and vigorously with steam to produce MgO and not magnesium hydroxide
+ reactivity increases down the group so reaction more vigorous down the group
How does the atomic radius change down the group?
+ form +2 ions when they react and lose two electrons
+ electronic configurations end in s2
+ atomic radius increases down the group
+ extra shells added as we go down the group
What is the trend in first ionisation energy down group 2?
+ decreases down the group and reactivity increases
+ atomic radius increases and there are more electron shells
+ there is more shielding
+ nuclear attraction to the outermost electrons decreases
+ less energy required to remove outermost electrons
How do group 2 elements react with dilute acids?
+ form salt and hydrogen gas
+ reactivity increases down the group
How do group 2 oxides react with water?
+ react readily with water
+ releases OH- ions to form an alkaline solution of metal hydroxide
+ group 2 hydroxides are slightly soluble in water
+ excess metal and hydroxide ions form a solid precipitate when the solution is saturated
+ MgO reacts very slowly and the hydroxide barely dissolves
+ more strongly alkaline down the group as the hydroxides become more soluble
How does the solubility of hydroxides change down group 2?
+ increases down the group
+ resulting solutions contain more OH- (aq) ions and become more alkaline
Why can group 2 compounds be used as bases?
related to basic properties and ability to neutralise acids
How are group 2 compounds used in agriculture?
+ Ca(OH)2 - calcium hydroxide/ slaked lime used to neutralise acidic soils
+ neutralises the acid in soils to increase the pH and form water
How can group 2 compounds be used in medicine?
+ antacids for treating acid indigestion
+ many indigestion tablets use Mg and Ca carbonates as main ingredients
+ 'milk of magnesia' - suspension of white magnesium hydroxide in water
+ magnesium hydroxide only slightly soluble in water
What is the reaction of slaked lime/ calcium hydroxide neutralising acid in soils?
Ca(OH)2 (s) + 2HCl (aq) -> CaCl2 (aq) + 2H2O (l)
What is the reaction of magnesium hydroxide neutralising stomach acid?
Mg(OH)2 (g) + 2HCl (aq) -> MgCl2 (aq) + 2H2O (l)
What is the reaction when calcium carbonate is used as an antacid to treat indigestion?
CaCO3 (s) + 2HCl (aq) -> CaCl2 (aq) + H2O (l) + CO2 (g)
How does metal hydroxide solubility and alkalinity change down group 2?
+ increases down group as metal hydroxides become more soluble in water
+ more soluble metal hydroxides dissolve more OH- ions in solutions
+ increase OH- ion concentration which increases alkalinity of metal hydroxides as you go down group 2
What are the building and construction uses of group 2 compounds?
+ calcium carbonate used as building material and present in both limestone and marble
+ limestone and marble used to make buildings
+ drawback of using calcium carbonate is they readily react with acid to form acid rain which causes calcium carbonate in limestone or marble to erode