group 2 Flashcards
why is magnesiums BP lower than expected
has a different crystal structure to the rest of the group
what are group 2 elements called and why
alkaline earth metals
-alkaline because they make alkalis when reacting with water
-earth because theyre less soluble than group 1
group 2 physical properties- atomic radius (4)
-increases down group
-more electron shells
-more shielding
-less attraction between outer shell e- and nucleus as e- is further away
group 2 physical properties- first ionisation energy (4)
-decreases down the group
-more electron shells
-more shielding
-less attraction between outer e- and nucleus
group 2 physical properties- melting points (4)
-decrease down group
-larger atomic radius
-less attraction between delocalised electrons
-weaker metallic bonding
equation for reaction between group 2 and water
M + H2O(l) –> M(OH)2(aq) + H2(g)
equation for reaction between group 2 and steam
M + H2O(g) –> MO +H2
3 observations and why for reaction of magnesium and steam
-gas produced burns due to flammable hydrogen produced
-bright white light of Mg due to exothermic reaction
-white solid produced due to magnesium oxide produced
4 observations and why for reaction of calcium and water
-gets hot due to exothermic reaction
-bubbles, burning splint, squeaky pop sound due to flammable hydrogen produced
-goes cloudy (white solid formed) due to calcium hydroxide being sparingly soluble
-pH 12 (purple) due to alkali produced
group 2 chemical property- reactivity (5)
-increases down the group
-outer e- further from nucleus
-more shielding
-less nuclear attraction
-outer e- more easily lost
why should water never be used to put out a group 2 metal fire eg. magnesium fire
-Mg reacts with water to produce H2 which forms an explosive mixture with air
properties of titanium (3)
-very high MP
-non toxic
-unreactive
how is Mg used to extract Ti from TiCl4- first step (equation)
TiO2 + 2C +2Cl2 –> TiCl4 + 2CO
how is Mg used to extract Ti from TiCl4- second step (equation)
TiCl4 + 2Mg –> 2MgCl2 +Ti
write a half equation for magnesium in TiCl4 + 2Mg –> 2MgCl2 +Ti
Mg –> Mg2+ + 2e-
what is a reducing agent (2)
-donates electrons to another species
-it gets oxidised so it causes reduction
what is calcium hydroxide, Ca(OH)2, used for and why (3)
-its a base and is aqueous
-used to neutralise acidic soil
-provides calcium ions essential for plant growth
what is magnesium hydroxide. Mg(OH)2, used for and why (3)
-antacids- indigestion tablet
-its a base and insoluble solid
-indigestion caused by excess stomach acid (HCl)
how does calcium oxide/calcium carbonate remove sulfur dioxide (2 and 2 equations)
-sulfur dioxide= acid, calcium oxide/carbonate= base
-can be used to neutralise the gas, producing a solid
CaO(s) + SO2 (g) –> CaSO3(s)
CaCO3(s) + SO2 (g) –> CaSO3(s) + CO2(g)
