alkaline earth metals beryllium magnesium calcium strontium barium radium
TRANSCRIPT
![Page 1: Alkaline Earth Metals Beryllium Magnesium Calcium Strontium Barium Radium](https://reader033.vdocuments.us/reader033/viewer/2022061509/56649c815503460f94939856/html5/thumbnails/1.jpg)
Alkaline Earth MetalsBeryllium
Magnesium
Calcium
Strontium
Barium
Radium
![Page 2: Alkaline Earth Metals Beryllium Magnesium Calcium Strontium Barium Radium](https://reader033.vdocuments.us/reader033/viewer/2022061509/56649c815503460f94939856/html5/thumbnails/2.jpg)
• Why were these elements called “alkaline earth
metals”?
• What do you think about the uses of these elements
commonly?
Alkaline Earth Metals
![Page 3: Alkaline Earth Metals Beryllium Magnesium Calcium Strontium Barium Radium](https://reader033.vdocuments.us/reader033/viewer/2022061509/56649c815503460f94939856/html5/thumbnails/3.jpg)
![Page 4: Alkaline Earth Metals Beryllium Magnesium Calcium Strontium Barium Radium](https://reader033.vdocuments.us/reader033/viewer/2022061509/56649c815503460f94939856/html5/thumbnails/4.jpg)
![Page 5: Alkaline Earth Metals Beryllium Magnesium Calcium Strontium Barium Radium](https://reader033.vdocuments.us/reader033/viewer/2022061509/56649c815503460f94939856/html5/thumbnails/5.jpg)
• The word “earth” was used for the oxides of group 2A by the
ancient scientists.
• Alkaline earth metals, after the alkali metals, are secondary
metals with strong metallic properties.
• The group 2A elements are less active than those of 1A, but
more active than those of group 3A.
• Except Be, all form ionic compounds.
• Be forms mostly covalent compounds.
![Page 6: Alkaline Earth Metals Beryllium Magnesium Calcium Strontium Barium Radium](https://reader033.vdocuments.us/reader033/viewer/2022061509/56649c815503460f94939856/html5/thumbnails/6.jpg)
• The atomic radius increases from top to bottom.
•The melting point, boiling point and the hardness of the elements decrease from top to bottom.
• Beryllium is the hardest alkaline earth metal
• Barium is the softest alkaline earth metal.
• Malleable and ductile.
• Excess Mg+2 and Ca+2 in water means that it is hard.
![Page 7: Alkaline Earth Metals Beryllium Magnesium Calcium Strontium Barium Radium](https://reader033.vdocuments.us/reader033/viewer/2022061509/56649c815503460f94939856/html5/thumbnails/7.jpg)
Characteristic Flame Colors of Alkaline Earth Metals
BariumCalcium StrontiumMagnesium
![Page 8: Alkaline Earth Metals Beryllium Magnesium Calcium Strontium Barium Radium](https://reader033.vdocuments.us/reader033/viewer/2022061509/56649c815503460f94939856/html5/thumbnails/8.jpg)
Minerals of Some Alkaline Earth Metals
![Page 9: Alkaline Earth Metals Beryllium Magnesium Calcium Strontium Barium Radium](https://reader033.vdocuments.us/reader033/viewer/2022061509/56649c815503460f94939856/html5/thumbnails/9.jpg)
Chemical Properties
• They are Covered by their oxides when they are exposed to
air.
• Burn in air with bright flame.
•Activity of the metals increases from Be to Ba.
• Reactions of Ca, Sr and Ba are easy with water.
• Reactions of Be and Mg with water are difficult.
![Page 10: Alkaline Earth Metals Beryllium Magnesium Calcium Strontium Barium Radium](https://reader033.vdocuments.us/reader033/viewer/2022061509/56649c815503460f94939856/html5/thumbnails/10.jpg)
Chemical Properties
• Ca (s) + 2H2O(l) → Ca+2(aq) + 2OH-(aq) + H2(g)
• Mg (s) + 2H2O(l) → Mg(OH)2(s) + H2(g)
• 2Mg (s) + O2(g) → 2MgO(s)
• Mg (s) + H2(g) → MgH2(s)
• Ca (s) + 2HCI(aq) → CaCl2 + H2(g)
• Be (s) + 2HCI(aq) → BeCI2 + H2(g)
• All oxides and hydroxides of alkaline earth metals show basic properties.
• Oxides and its hydroxides of beryllium show amphoteric properties.
![Page 11: Alkaline Earth Metals Beryllium Magnesium Calcium Strontium Barium Radium](https://reader033.vdocuments.us/reader033/viewer/2022061509/56649c815503460f94939856/html5/thumbnails/11.jpg)
Compounds
• Ionic
• Have high melting and boiling points.
• Thermally stable.
• Less soluble in water than those of 1A metals.
• Solubility of salts increase from Be to Ba.
![Page 12: Alkaline Earth Metals Beryllium Magnesium Calcium Strontium Barium Radium](https://reader033.vdocuments.us/reader033/viewer/2022061509/56649c815503460f94939856/html5/thumbnails/12.jpg)
• Obtained by heating calcium
carbonate (limestone) at 900°C.
• CaCO3(s) → CaO(s) + CO2(g)
Calcium Oxide, CaO
Calcium Carbonate, CaCO3
• It forms by evolving CO2 gas from Ca(OH)2 solution.
![Page 13: Alkaline Earth Metals Beryllium Magnesium Calcium Strontium Barium Radium](https://reader033.vdocuments.us/reader033/viewer/2022061509/56649c815503460f94939856/html5/thumbnails/13.jpg)
• Small gray solid pieces
• Used widely in industry
• Prepared by the reaction of calcium oxide (lime) and coke.
CaO(s) + 3C(s) ↔ CaC2(s) + CO (g)
CaC2(s) + 2H2O(l) → C2H2(g) + Ca(OH)2(s)
Calcium Carbide, CaC2
![Page 14: Alkaline Earth Metals Beryllium Magnesium Calcium Strontium Barium Radium](https://reader033.vdocuments.us/reader033/viewer/2022061509/56649c815503460f94939856/html5/thumbnails/14.jpg)
CaSO4.2H2O : Gypsum
CaSO4.1/2H2O : Plaster of Paris
• Gypsum is a white substance and
used for fabrication into wallboard.
Calcium Sulfate, CaSO4
![Page 15: Alkaline Earth Metals Beryllium Magnesium Calcium Strontium Barium Radium](https://reader033.vdocuments.us/reader033/viewer/2022061509/56649c815503460f94939856/html5/thumbnails/15.jpg)
Uses
• Very light element
• To prepare some special alloys.
• 2% Be in Cu alloy in springs.
• Making glass for X-ray tubes.
• In the aerospace industry.
Beryllium
![Page 16: Alkaline Earth Metals Beryllium Magnesium Calcium Strontium Barium Radium](https://reader033.vdocuments.us/reader033/viewer/2022061509/56649c815503460f94939856/html5/thumbnails/16.jpg)
Uses
• Light metal
• Production of planes, missiles
• Some light household items.
• Flash in photography
Magnesium
![Page 17: Alkaline Earth Metals Beryllium Magnesium Calcium Strontium Barium Radium](https://reader033.vdocuments.us/reader033/viewer/2022061509/56649c815503460f94939856/html5/thumbnails/17.jpg)
• To increase the hardness, durability and
resistance to corrosion of alloys.
• Additive in rocket fuels and signal
rockets.
• Mg(OH)2 is used as a stomach antacid.
Magnesium
![Page 18: Alkaline Earth Metals Beryllium Magnesium Calcium Strontium Barium Radium](https://reader033.vdocuments.us/reader033/viewer/2022061509/56649c815503460f94939856/html5/thumbnails/18.jpg)
• Construction materials, bleaching agents.
• CaO in the production of some chemicals, steel, glass, paper
and sugar.
• CaC2 is used to produce acetylene gas
for welding.
• In fertilizers and
toothpaste
Calcium Compounds
![Page 19: Alkaline Earth Metals Beryllium Magnesium Calcium Strontium Barium Radium](https://reader033.vdocuments.us/reader033/viewer/2022061509/56649c815503460f94939856/html5/thumbnails/19.jpg)
• Ba is used as a gas absorbent in vacuum tubes.
• The alloys of Ba with Ni donate electrons so used in vacuum
tubes and in ignitors and spark plugs.
• Barium nitrate and barium chlorate are used to obtain green
light in fireworks.
Barium and Its Compounds
![Page 20: Alkaline Earth Metals Beryllium Magnesium Calcium Strontium Barium Radium](https://reader033.vdocuments.us/reader033/viewer/2022061509/56649c815503460f94939856/html5/thumbnails/20.jpg)
• BaSO4 is used to take the photos of stomach and intestines.
• Ba does not allow X-rays to pass like all elements with large
atomic number.
•The Ba+2 ion is toxic, but since the solubility of BaSO4 in
water is very low, its poisonous effect disappears.
Barium and Its Compounds
![Page 21: Alkaline Earth Metals Beryllium Magnesium Calcium Strontium Barium Radium](https://reader033.vdocuments.us/reader033/viewer/2022061509/56649c815503460f94939856/html5/thumbnails/21.jpg)
• The salts of strontium in signal rockets and fireworks to
produce red light.
• Nuclear batteries.
Strontium
![Page 22: Alkaline Earth Metals Beryllium Magnesium Calcium Strontium Barium Radium](https://reader033.vdocuments.us/reader033/viewer/2022061509/56649c815503460f94939856/html5/thumbnails/22.jpg)
• In self luminous paints and in radiotherapy.
• As a neutron source.
• On luminous watch dials.
Radium