Views: 43
Chemical Properties of S-Block Elements
- Atomic and Ionic Radii
The size of the alkali metals is larger compared to other elements in a particular period. As the atomic number increases the total number of electrons increases along with the addition of shells.
On moving down the group the atomic number increases. As a result, the atomic and ionic radius of the alkali metals increases.
2. Ionization energy
As we go down the group the size of the atoms increases due to which the attraction between the nucleus and the electrons in the outermost shell decreases. As a result, the ionization energy decreases. The ionization energy of the alkali metals is comparatively lesser than other elements.
3. Hydration energy
As the ionic sizes of the elements increase, the hydration energy decreases. The smaller the size of the ion, the higher the hydration energy. this is because the atom has the capacity to accommodate a larger number of water molecules around it due to the high charge/radius ratio and hence gets hydrated.
Diagonal Relationship within S-Block Elements
A diagonal relationship in S block elements exists between adjacent elements which are located in the second and third period of the periodic table. For example, Lithium of group 1A and second period shows similarities with the properties of magnesium which are located in the 2nd group and 3rd period.
Similarly, properties of beryllium which are located in the 2nd group and 2nd period show a likeness with properties of aluminium which is located in the third period and third group. The two elements which show similarities in their properties can be called a diagonal pair or diagonal neighbours.
The properties of S block elements vary significantly when compared to the other elements of the sub-group they belong to. The diagonal neighbours show a lot of similarities. Such a relationship is exhibited as you move left to right and down the group; the periodic table has opposing factors.
Similarities between Lithium and Magnesium
- The hardness of lithium and magnesium is higher than the other elements in their respective groups.
- Chlorides of lithium and magnesium have the capability to be soluble in ethanol.
- They are lighter when compared to other elements in their groups.
- Lithium and magnesium react gently with water. The oxides and hydroxides are less soluble.
- In the presence of nitrogen, lithium and magnesium form their respective nitrides.
- Superoxides are not formed when lithium and magnesium react with excess oxygen.
- Carbon dioxide and its respective oxidesare formed when carbonates of magnesium and lithium are heated.
Similarities between Beryllium and Aluminum
- Aluminium hydroxideand beryllium hydroxide react with excess alkali to form their respective ions.
- Both these elements have the capacity to withstand the acid attack due to the presence of an oxide film on the surface of the metal.
- Both these metals have the tendency to form complexes.
- Chlorides of both these metals possess the capacity to be soluble in organic solvents.
General Types of Matter
Elements are divided between metals and nonmetals several elements with properties of both metals and nonmetals are called metalloids. Metals are elements that are generally solid, shiny in appearance, electrically conducting, and malleable (that is, they can be pounded into flat sheets without disintegrating. Nonmetals often have a dull appearance and are not at all malleable. nonmetals frequently occur as gases or liquids. Colorless oxygen gas, green chlorine gas and brown bromine liquid are common nonmetals.
Organic substances consist of virtually all compounds that contain carbon, including substances made by life processes (wood, flesh, cotton, wool), petroleum, natural gas (methane), solvents (dry cleaning fluids), synthetic fibers, and plastics. All of the rest of the chemical kingdom is composed of inorganic substances made up of virtually all substances that do not contain carbon.