1.2.9
Alkaline Earth Metals
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Properties of Group 2 Metals
Elements in the same group have similar properties. Here, we shall look at the similarities between the properties of the Group 2 elements.
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Atomic radius and ionisation energy
- Atomic radius increases as you go down Group 2.
- This is because each extra electron shell is further away.
- Ionisation energy decreases as you go down Group 2.
- This is because the outer electrons are further away and experience less attraction to the nucleus.

Melting point
- Melting points decrease as you go down Group 2.
- This is because the ion cores have larger radii down the group.
- The free electrons experience less attraction to the nuclei because of the larger radii.
- The bonding is weaker, so the melting point is lower.
- Magnesium has an anomalously low melting point.
- This is because it has a different crystal structure to the rest of Group 2.

Reactions with water
- Group 2 metals react with water to form metal hydroxides. For example:
- Mg + 2H2O → Mg(OH)2 + H2
- Reactivity increases as you go down Group 2. This is because the lower elements have lower ionisation energies.
- Beryllium is an exception. If beryllium were to lose two electrons it would be tiny and have a very high charge density. This would make it unstable and so beryllium doesn't react with water.

Solubility of salts
- The solubility of hydroxides increases as you go down Group 2.
- Magnesium hydroxide is very insoluble. The phrase to use for this is 'sparingly soluble'.
- The solubility of sulfates decreases as you go down Group 2.
- Barium sulfate is completely insoluble.
Uses of Group 2 Compounds
Group 2 compounds have a number of uses in industry and society. Examples of these uses include:

Titanium extraction
- The first step in the extraction process is converting titanium ore (TiO2) to titanium chloride (TiCl4) using chlorine gas and carbon.
- The second step involves heating TiCl4 with magnesium metal at 1,000oC. The equation for this step is:
- TiCl4(g) + 2Mg(l) Ti(s) + 2MgCl2(l)

As bases to neutralise acids
- Calcium hydroxide (sometimes called slaked lime) and magnesium hydroxide are used to neutralise acids.
- Calcium hydroxide is used to neutralise acidic soils in agriculture.
- Magnesium hydroxide is used in indigestion tablets as an antacid that neutralises excess stomach acid.

In healthcare
- 'Barium meals' (made of barium sulfate) are used in healthcare.
- X-rays can detect solid materials like bones but aren't very good at detecting soft tissues.
- 'Barium meals' are insoluble and reflect X-rays.
- A barium meal coats the oesophagus, stomach, and intestines and makes the structure of them show up on X-rays.

Wet scrubbing
- Wet scrubbing is the process of removing SO2 from flue gases.
- Flue gases come from chimneys and industrial waste.
- CaO and CaCO3 are used to remove the SO2 from the gases.
- This works because SO2 is acidic and the calcium compounds are bases.
- The CaO is mixed with water and sprayed onto the gases.
- The byproduct is calcium sulfite, CaSO3.
1Principles of Science I
1.1Structure & Bonding
1.1.1Atomic Model1.1.2Electron Shells, Sub-Shells & Orbitals1.1.3Ionic Bonding1.1.4Representing Ionic Bonds1.1.5Covalent Bonding1.1.6Representing Covalent Bonds1.1.7Metallic Bonding1.1.8Intermolecular Forces1.1.9Intermolecular Forces 21.1.10End of Topic Test - Bonding1.1.11Relative Masses1.1.12The Mole1.1.13Molar Calculations1.1.14Molar Calculations 21.1.15Empirical & Molecular Formulae1.1.16Balanced Equations1.1.17Percentage Yield1.1.18End of Topic Test - Amount of Substance
1.2Properties of Substances
1.2.1The Periodic Table1.2.2Ionisation Energy1.2.3Factors Affecting Ionisation Energies1.2.4Trends of Ionisation1.2.5Trends in the Periodic Table1.2.6Polarity1.2.7Metals & Non-Metals1.2.8Alkali Metals1.2.9Alkaline Earth Metals1.2.10Reactivity of Alkaline Earth Metals1.2.11Redox1.2.12Transition Metals1.2.13Redox Reactions of Transition Metals
1.3Cell Structure & Function
1.4Cell Specialisation
1.5Tissue Structure & Function
1.5.1Human Gas Exchange1.5.2Blood Vessels1.5.3Atherosclerosis1.5.4Skeletal Muscle1.5.5Slow & Fast Twitch Fibres1.5.6Neurones1.5.7Speed of Transmission1.5.8Action Potentials1.5.9End of Topic Test - Neurones & Action Potentials1.5.10Synapses1.5.11Types of Synapse1.5.12Medical Application1.5.13End of Topic Test - Synapses1.5.14Chemical Brain Imbalances1.5.15Effect of Drugs on the Brain
1.6Working with Waves
1.7Waves in Communication
2Practical Scientific Procedures and Techniques
3Science Investigation Skills
3.1Scientific Processes
3.2Data Handling & Analysis
3.3Enzymes in Action
3.4Diffusion
3.5Plants & Their Environment
3.6Energy Content in Fuels
4Principles of Science II
4.1Extracting Elements
4.2Relating Properties to use of Substances
4.3Organic Chemistry
4.4Energy Changes in Industry
4.5The Circulatory System
4.5.1The Circulatory System4.5.2Blood Vessels4.5.3Blood Transfusion & the ABO Rhesus System4.5.4The Heart4.5.5The Cardiac Cycle4.5.6Cardiac Output4.5.7Coordination of Heart Action4.5.8Heart Dissection4.5.9Controlling Heart Rate4.5.10Electrocardiograms4.5.11Cardiovascular Disease4.5.12Investigating Heart Rates
4.6Ventilation & Gas Exchange
4.7Urinary System
4.9Thermal Physics
4.9.1Power & Efficiency4.9.2Work & Energy4.9.3Conservation of Energy4.9.4Pressure4.9.5First Law of Thermodynamics4.9.6Second Law of Thermodynamics4.9.7Heat Engines, Heat Pumps & Refrigerators4.9.8Non-Flow Processes4.9.9p-V Diagrams4.9.10Ideal Gases4.9.11Ideal Gases 24.9.12Thermal Energy Transfer4.9.13Thermal Energy Transfer Experiments
4.10Materials
5Contemporary Issues in Science
5.1Contemporary Issues in Science
5.2Analysing Scientific Information
Jump to other topics
1Principles of Science I
1.1Structure & Bonding
1.1.1Atomic Model1.1.2Electron Shells, Sub-Shells & Orbitals1.1.3Ionic Bonding1.1.4Representing Ionic Bonds1.1.5Covalent Bonding1.1.6Representing Covalent Bonds1.1.7Metallic Bonding1.1.8Intermolecular Forces1.1.9Intermolecular Forces 21.1.10End of Topic Test - Bonding1.1.11Relative Masses1.1.12The Mole1.1.13Molar Calculations1.1.14Molar Calculations 21.1.15Empirical & Molecular Formulae1.1.16Balanced Equations1.1.17Percentage Yield1.1.18End of Topic Test - Amount of Substance
1.2Properties of Substances
1.2.1The Periodic Table1.2.2Ionisation Energy1.2.3Factors Affecting Ionisation Energies1.2.4Trends of Ionisation1.2.5Trends in the Periodic Table1.2.6Polarity1.2.7Metals & Non-Metals1.2.8Alkali Metals1.2.9Alkaline Earth Metals1.2.10Reactivity of Alkaline Earth Metals1.2.11Redox1.2.12Transition Metals1.2.13Redox Reactions of Transition Metals
1.3Cell Structure & Function
1.4Cell Specialisation
1.5Tissue Structure & Function
1.5.1Human Gas Exchange1.5.2Blood Vessels1.5.3Atherosclerosis1.5.4Skeletal Muscle1.5.5Slow & Fast Twitch Fibres1.5.6Neurones1.5.7Speed of Transmission1.5.8Action Potentials1.5.9End of Topic Test - Neurones & Action Potentials1.5.10Synapses1.5.11Types of Synapse1.5.12Medical Application1.5.13End of Topic Test - Synapses1.5.14Chemical Brain Imbalances1.5.15Effect of Drugs on the Brain
1.6Working with Waves
1.7Waves in Communication
2Practical Scientific Procedures and Techniques
3Science Investigation Skills
3.1Scientific Processes
3.2Data Handling & Analysis
3.3Enzymes in Action
3.4Diffusion
3.5Plants & Their Environment
3.6Energy Content in Fuels
4Principles of Science II
4.1Extracting Elements
4.2Relating Properties to use of Substances
4.3Organic Chemistry
4.4Energy Changes in Industry
4.5The Circulatory System
4.5.1The Circulatory System4.5.2Blood Vessels4.5.3Blood Transfusion & the ABO Rhesus System4.5.4The Heart4.5.5The Cardiac Cycle4.5.6Cardiac Output4.5.7Coordination of Heart Action4.5.8Heart Dissection4.5.9Controlling Heart Rate4.5.10Electrocardiograms4.5.11Cardiovascular Disease4.5.12Investigating Heart Rates
4.6Ventilation & Gas Exchange
4.7Urinary System
4.9Thermal Physics
4.9.1Power & Efficiency4.9.2Work & Energy4.9.3Conservation of Energy4.9.4Pressure4.9.5First Law of Thermodynamics4.9.6Second Law of Thermodynamics4.9.7Heat Engines, Heat Pumps & Refrigerators4.9.8Non-Flow Processes4.9.9p-V Diagrams4.9.10Ideal Gases4.9.11Ideal Gases 24.9.12Thermal Energy Transfer4.9.13Thermal Energy Transfer Experiments
4.10Materials
5Contemporary Issues in Science
5.1Contemporary Issues in Science
5.2Analysing Scientific Information
Practice questions on Alkaline Earth Metals
Can you answer these? Test yourself with free interactive practice on Seneca — used by over 10 million students.
- 1Key properties of Group 2 metals:Fill in the list
- 2Melting point trend down Group 2:Fill in the list
- 3Why is magnesium's melting point lower than expected?Multiple choice
- 4Uses of Group 2 compounds:Fill in the list
- 5Group 2 compounds as bases:Fill in the list
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