Group 2 elements are known as alkaline earth metals.
They are located in Group 2 of the periodic table.
The group includes beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).
These elements have similar properties due to their similar electronic configurations.
Electronic Configuration
The electronic configuration of Group 2 elements is ns^2.
Each element in the group has two valence electrons.
The valence electrons are in the s orbital.
General Properties of Group 2 Elements
Metallic nature:
Group 2 elements are metals.
They exhibit typical metallic properties such as high electrical and thermal conductivity.
They are malleable and ductile.
Atomic size:
Group 2 elements have larger atomic size compared to the corresponding elements in Group 1.
Atomic size increases down the group.
Ionization energy:
Ionization energy is the energy required to remove an electron from an atom or ion.
Group 2 elements have higher ionization energies compared to the corresponding elements in Group 1.
Reactivity:
Group 2 elements are highly reactive.
They readily lose their two valence electrons to form 2+ cations.
Oxidation states:
Group 2 elements predominantly exhibit +2 oxidation state.
They can form compounds with other elements by losing two electrons.
Trends in Atomic and Ionic Radii
Atomic radius is the size of an atom, and ionic radius is the size of an ion.
Atomic and ionic radii generally increase down the group.
This trend is due to the addition of new energy levels as we move down the periodic table.
Atomic radius decreases as we move across a period, from left to right.
Chemistry of Group 2 Elements
Recap of the key points discussed so far:
Group 2 elements are alkaline earth metals.
Their electronic configuration is ns^2.
They are highly reactive and form 2+ cations.
Atomic and ionic radii increase down the group.
Comparing Group 1 and Group 2 Elements
Group 1 elements (alkali metals) and Group 2 elements (alkaline earth metals) have similar properties.
However, there are some key differences between these two groups.
Let’s compare them side by side:
| Property | Group 1 Elements (Alkali Metals) | Group 2 Elements (Alkaline Earth Metals) |
|–||–|
| Valence Electrons | 1 | 2 |
| Reactivity | Highly reactive | Highly reactive |
| Oxidation States | +1 | +2 |
| Ionization Energies | Lower than Group 2 elements | Higher than Group 1 elements |
| Atomic and Ionic Size | Larger than Group 2 elements | Smaller than Group 1 elements |
Applications of Group 2 Elements
Group 2 elements find various applications in different fields.
Some of the important applications are:
Magnesium is used as a lightweight metal in the aerospace industry.
Calcium is essential for the formation of bones and teeth in humans.
Barium compounds are used in X-ray examinations to enhance image contrast.
Group 2 Elements in Everyday life
Group 2 elements have a significant presence in our everyday life.
Here are some examples:
Beryllium-aluminum alloy is used in aerospace components.
Magnesium oxide is used as an antacid to treat heartburn and indigestion.
Calcium carbonate is used as a supplement for calcium intake.
Chemistry of Group 2 Elements
Group 2 elements are also known as alkaline earth metals.
They are located in Group 2 of the periodic table.
Group 2 elements include beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).
These elements have similar properties due to their similar electronic configurations.
Group 2 elements have two valence electrons in their outermost shell.
Electronic Configuration
The electronic configuration of Group 2 elements is ns^2.
The valence electrons of Group 2 elements are located in the s orbital of their outermost energy level.
The ns^2 configuration makes these elements highly reactive.
The presence of two valence electrons facilitates the formation of +2 cations.
General Properties of Group 2 Elements
Atomic Size:
Atomic size generally increases down the group.
This is due to the addition of new energy levels as we move down the periodic table.
The increase in atomic size results in weaker attractive forces between the nucleus and electrons.
Ionization Energy:
Ionization energy is the energy required to remove an electron from an atom or ion in the gaseous state.
Group 2 elements have higher ionization energies compared to Group 1 elements.
This is because Group 2 elements have a smaller atomic size and stronger nuclear attraction.
Metallic Nature:
Group 2 elements are metals.
They have lustrous appearances and high electrical and thermal conductivity.
The metallic nature increases down the group.
Reactivity:
Group 2 elements are highly reactive.
They readily lose their two valence electrons to attain stable electronic configurations.
Their reactivity increases down the group.
Oxidation States:
Group 2 elements predominantly exhibit a +2 oxidation state.
They lose two valence electrons to achieve a stable octet configuration.
However, they can exhibit different oxidation states in certain compounds and reactions.
Trends in Reactivity
Alkali earth metals exhibit increasingly higher reactivity down the group.
This is due to their low ionization energies and the ease of losing two valence electrons.
For example, magnesium (Group 2) is less reactive than sodium (Group 1) but more reactive than beryllium (Group 2).
The reactivity of alkaline earth metals leads to the formation of stable 2+ cations.
Examples of Group 2 Compounds
Calcium Carbonate (CaCO3):
Found in limestone, marble, and chalk.
Used as a dietary supplement for calcium intake.
Important in the construction industry as a building material.
Magnesium Oxide (MgO):
An antacid used to treat heartburn and indigestion.
Used in the production of refractory materials, such as crucibles and furnace linings.
Barium Sulfate (BaSO4):
Used as a contrast agent for X-ray examinations to enhance image contrast.
Barium sulfate is opaque to X-rays, allowing doctors to visualize certain body structures more clearly.
Strontium Nitrate (Sr(NO3)2):
Used in fireworks to produce red flame/color.
Beryllium Alloy:
Beryllium-aluminum alloy is used in aerospace components because of its lightweight and high thermal conductivity properties.
Chemical Reactions of Group 2 Elements
Group 2 elements tend to react with other elements to form compounds.
Some common reactions of Group 2 elements include:
Reaction with oxygen to form metal oxides.
Reaction with water to form metal hydroxides and hydrogen gas.
Reaction with acids to form metal salts and hydrogen gas.
Reaction with halogens to form metal halides.
Remember, understanding the chemistry of Group 2 elements is fundamental in understanding various chemical reactions and applications in everyday life.
Chemistry of Group 2 Elements - Summarize the salient features of Group 2 elements
Group 2 elements are alkaline earth metals
Include beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra)
Similar electronic configurations (ns^2)
Two valence electrons
Reactive metals, easily lose two electrons
Chemical Reactivity of Group 2 Elements
Reactivity increases down the group
Group 2 elements readily lose two valence electrons to form 2+ ions
Examples:
Magnesium (Mg) reacts with oxygen (O2) to form magnesium oxide (MgO)
Calcium (Ca) reacts with water (H2O) to form calcium hydroxide (Ca(OH)2) and hydrogen gas (H2)
Strontium (Sr) reacts with hydrochloric acid (HCl) to form strontium chloride (SrCl2) and hydrogen gas (H2)
Trends in Ionization Energy
Ionization energy increases from top to bottom in Group 2 elements
Atoms become smaller, with stronger nuclear attraction
More difficult to remove valence electrons
Higher ionization energy values
Example: Ionization energies of Group 2 elements: Be < Mg < Ca < Sr < Ba
Formation of Oxides
Group 2 elements react with oxygen to form metal oxides
General equation: 2M (s) + O2 (g) → 2MO (s)
Examples:
Magnesium + Oxygen → Magnesium Oxide: 2Mg (s) + O2 (g) → 2MgO (s)
Calcium + Oxygen → Calcium Oxide: 2Ca (s) + O2 (g) → 2CaO (s)
Formation of Hydroxides
Group 2 elements react with water to form metal hydroxides and hydrogen gas
General equation: M (s) + 2H2O (l) → MOH2 (aq) + H2 (g)
Examples:
Magnesium + Water → Magnesium Hydroxide + Hydrogen: Mg (s) + 2H2O (l) → Mg(OH)2 (aq) + H2 (g)
Calcium + Water → Calcium Hydroxide + Hydrogen: Ca (s) + 2H2O (l) → Ca(OH)2 (aq) + H2 (g)
Formation of Salts
Group 2 elements react with acids to form metal salts and hydrogen gas
General equation: M (s) + 2HCl (aq) → MCl2 (aq) + H2 (g)
Chemistry of Group 2 Elements Salient features of Group 2 elements Overview of Group 2 elements Electronic configuration General properties Trends in atomic and ionic radii