(i) Sodium and potassium ions maintain the ion balance and nerve impulse conduction.
(ii) Transport of sugar and amino acids into cells.
(iii) Potassium ions activate many enzymes, participate in the oxidation of glucose to produce ATP.
(iv) With sodium, potassium ion is responsible for the transmission of nerve signals.
(v) Sodium and potassium pump play an important role in transmitting nerve signals.

(i) Lithium metal is used to make alloys.
(ii) Lithium is also used to make electrochemical cells.
(iii) Lithium carbonate is used in medicines.

On moving down the group, there is an increase in the number of shells, as well as increase in nuclear charge. The force of attraction between the nucleus and the added electron decreases. Hence, ionic and atomic radii increases.

Efflorescence is the spontaneous loss of water by a hydrated salt, which occurs when the aqueous vapor pressure of the hydrate is greater than the partial pressure of the water vapour in the air. This is the property of salts
Ex: Glauber's salt- Na₂SO₄·10H₂O
Epsom salt - MgSO₄·7H₂O

(i)\(Li_2CO_3+\xrightarrow{Δ}Li_2O+CO_2\)
(ii) This is presumably due to large size difference between Li⁺ and \(CO_2^{ -3}\) which makes the crystal lattice unstable and decomposes readily

This is due to large size difference between Li⁺ and  which makes the crystal lattice unstable

(i) Lithium metal is used to make useful alloys. For example with lead it is used to make 'white metal' bearings for motor engines, with aluminium to make aircraft parts, and with magnesium to make armour plates. It is used in thermonuclear reactions.
(ii) Lithium is also used to make electrochemical cells.
(iii) Lithium carbonate is used in medicines
(iv) Sodium is used to make Na/Pb alloy.
(v) Liquid sodium metal is used as a coolant in fast breeder nuclear reactors.
(vi) Potassium chloride is used as a fertilizer. Potassium hydroxide is used in the manufacture of soft soap. It is also used as an excellent absorbent of carbon dioxide.
(vii) Caesium is used in devising photoelectric cells.

The high solubility of lithium salts is due to strong solvation of small size Li⁺ ion

Alkali metals have one e^o in their outer most shell. Alkaline earth metals have 2 e^o in their outer most shell. More valence electrons and more positively charged nucleii leads to greater opportunity for metallic bonding.

The largest use of plaster of paris is in the building industry as well as plasters. It is used for immobilising the affected part of organ where there is a bone fracture or sprain. It is also employed in dentistry, in ornamental work and for making casts of statues and busts.

1. This group contains Be, Mg, Ca, Sr, Ba & Ra.
2. Except Be all these elements are called as alkaline earth metals because their oxides and hydroxides are alkaline in nature.
3. Beryllium is the rare element and Radium is the rarest (10% rocks) ; Their Occurrence: Be- Beryl; Mg - carnallite; Dolomite Ca - Fluorapatite; Sr - Celestite Ba - Barytes.
4. Radium is radioactive.
5. The general electronic configuration is :
[Noble gas] ns² eg. Be - [He] 2s²
6. On moving down the group the radii increase. Their atomic radii are smaller than alkali metals.
7. They exhibit +2 oxidation state.
8. The ionisation enthalpies are less than p - block elements due to large size. Down the group the ionisation enthalpy decreases.
9. The IE₁ of group 2 elements are greater than group 1 elements.
10. The IE₂ values are higher than that of alkali metals.
11. They are less electro Positive elements than alkali metals.
12. The hydration enthalpy decreases with increase in ionic radii.
13. MgCl₂ form MgCI₂ .6H₂O and CaCl₂ form CaCl₂.6H₂O
14. The electronegativity value decreases down the group.
15. With concentrated HCl They impart flame colour. Ca - Brick Red ; Sr - Crimson red and Barium - Apple Green.
16. All form metallic halides at elevated temperatures. M + X₂ + MX₂
17. All elements except Beryllium combine with hydrogen to form hydrides of formula MH₂.

Magnesium oxide in having higher melting point. The lattice energy of MgO & MgF₂ are 3938 and 2957 respectively.
MgO has +2, -2 charges, MgF₂ has +2, -1 charges. When the two charges are multiplied together, MgO results in larger amount of lattice energy since it has a higher charge, The strong attraction cause most ionic material to be hard and brittle and have high melting points.