Group 2 alkaline earth metals Flashcards
All group 2 elements are…
metals
What happens down the atomic radius for group 2?
-down group 2 atomic radius increases
-due to more filled shells
-so outer electron is further from the nucleus
What happens to ionisation energy down group 2?
-ionisation energy decreases down group 2 due to greater atomic radius
-and greater shielding
-therefore the outer electron is attracted less strongly, so less energy is required to remove an electron
What happens to melting point down group 2?
-melting point generally decreases down group 2 due to increased ionic radii so decrease in charge/size ratio of the ion
-so weaker metallic bonding
-so less energy required to break the metallic bonds
Discuss how magnesium reacts with water
-reacts very very slowly with cold water
-reacts readily with steam
What is the word and symbol equation for the reaction of magnesium and steam?
magnesium + steam —> magnesium oxide + hydrogen
Mg(s) +H2O (g) —> MgO(s) + H2(g)
How can you describe MgO(s)?
white solid
How do calcium, strontium, and barium all react with cold water?
vigorously
What is the word and symbol equation for calcium and cold water?
calcium + water —> calcium hydroxide + hydrogen
Ca(s) +2H2O (l) —> Ca(OH)2 (aq) + H2(g)
What is the observations when magnesium reacts with steam?
magnesium reacts with steam when heated :
-glows orange
-white solid MgO(s) formed
Discuss Ca(OH)2 in water and what it can be used for
Ca(OH)2 is only sparingly soluble in water, is also called limewater. tests for CO2 gas
What is the observation when calcium reacts with water?
cloudy white mixture formed
What is the word and symbol equation for the reaction of strontium and water?
strontium + water —> strontium hydroxide + hydrogen
Sr(s) + 2H2O(l) —> Sr(OH)2 (aq) + H2(g)
What is the observation when strontium reacts with water and why?
Sr(OH)2 is more soluble than Ca(OH)2 in water so a colourless solution is formed
What is the word and symbol equation for the reaction of barium and water?
barium + water —> barium hydroxide + hydrogen
Ba(s) + 2H20(l) —> Ba(OH)2 (aq) + H2(g)