Question

Write the points of similarities and differences of alkali metals and alkaline earth metals.

chem XI Q10

Answer 1

Similarities of alkali metals and alkaline earth metals:-

1. Group Classification:

   • Both alkali metals and alkaline earth metals are found in the s-block of the periodic table.
   • Alkali metals are in Group 1, while alkaline earth metals are in Group 2.

2. High Reactivity:

   • Both groups are highly reactive, though alkali metals are generally more reactive than alkaline earth metals.
   • They react with water to form hydroxides and release hydrogen gas, though the reactions are more vigorous for alkali metals.

3. Softness:

   • Both groups contain metals that are relatively soft compared to many other metals. Alkali metals are typically softer than alkaline earth metals.

4. Low Density:

   • Both alkali and alkaline earth metals have lower densities compared to most other metals, though alkali metals have lower densities overall.

5. Low Melting and Boiling Points:

   • Both groups have relatively low melting and boiling points compared to other metals, but alkali metals have lower melting and boiling points than alkaline earth metals.

Differences of alkali metals and alkaline earth metals:-

1. Chemical Reactivity:

   • Alkali metals (Group 1) are more reactive than alkaline earth metals (Group 2). For example, lithium, sodium, and potassium react explosively with water, while alkaline earth metals like magnesium and calcium react less violently.

2. Valence Electrons:

   • Alkali metals have one valence electron (ns^1), while alkaline earth metals have two valence electrons (ns^2). This difference affects their chemical reactivity and bonding.

3. Oxidation States:

   • Alkali metals typically form +1 oxidation states in their compounds. In contrast, alkaline earth metals generally form +2 oxidation states.

4. Density and Hardness:

   • Alkali metals tend to have lower densities and are softer than alkaline earth metals. For instance, lithium and sodium are much softer and less dense than magnesium and calcium.

5. Color of Flames:

   • Alkali metals produce distinctive flame colors when burned: lithium gives a red flame, sodium yields a bright yellow flame, and potassium produces a lilac flame. Alkaline earth metals also give characteristic flame colors, but these are typically less intense: magnesium burns with a bright white flame, and calcium gives an orange-red flame.

6. Occurrence:

   • Alkali metals are more reactive and do not occur freely in nature, being found only in compounds. Alkaline earth metals, while also reactive, are somewhat less so and can be found in the earth's crust in various minerals.

7. Melting and Boiling Points:

   • Alkali metals generally have lower melting and boiling points compared to alkaline earth metals. For example, lithium has a melting point of 180.5°C, whereas magnesium has a melting point of 650°C.

8. Compounds and Solubility:

   • Alkali metal compounds are generally more soluble in water compared to alkaline earth metal compounds. For instance, sodium chloride (table salt) is highly soluble in water, whereas calcium sulfate is only slightly soluble.

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Answer 2

Similarities between Alkali and Alkaline Earth Metals

1. Both metals are found in combined form, not in a free state.

2. they tarnish in moist air.

3. Both of them are obtained through the process of electrolysis from their fused chlorides.

4. They decompose on water liberating hydrogen gas and forming an alkaline solution of their hydroxides.

5. They are soft silvery white.

6. they are reducing in nature.

7. They are electropositive.

8. All combine with hydrogen, forming a hydride.

9. Their oxides are white and remain unchanged on heating and give hydroxide with water.

10. They combine with Cl₂, Br₂ and I₂ easily.

Differences between Alkali and Alkaline earth metals

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Answer 3

        *DIFFERENCES*

• ALKALI METALS

1. They are present in group-1 of periodic table
2. They have 1 electron in their outermost shell.
3. they are soft as they can be cut into pieces with a knife.
4. They have low ionization energy as compared to alkaline earth metals

• ALKALINE EARTH METALS
• They are present in group-2 of periodic table
• They have 2 electron in their outermost shell.
• they are harder than alkali metals.
• They have high ionization energy as compared to alkali metals.

     *SIMILARITIES*

1. Both are present in s-block of periodic table.
2. Both are able to lose their outermost electrons easily.
3. Both are malleable, ductile and have luster. 
4. Both are good conductors of electricity.

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