Chap 1

  Alkali metals are good conductors of Electricity?

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Answer explanation

Yes, alkali metals are good conductors of electricity due to their single valence electron, which allows them to easily lose that electron and conduct electric current effectively.

What is Flame Test? Mention the color of flames of Alkali metals.

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Answer explanation

A Flame Test is used to identify the presence of certain metal ions based on the color of the flame produced. Alkali metals produce distinct colors: Lithium (red), Sodium (yellow), Potassium (lilac), Rubidium (red-violet), and Cesium (blue).

Describe the group trends of Ionization Energy in group IIIA of Periodic table.

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Answer explanation

In group IIIA, ionization energy generally decreases down the group due to increased atomic size and electron shielding, making it easier to remove the outermost electron.

Which of the following alkaline earth metals is most abundant in the Earth's crust?

• Beryllium

• Magnesium

• Calcium

• Strontium

Answer explanation

Calcium is the most abundant alkaline earth metal in the Earth's crust, making up about 3.6% by weight. It is more prevalent than beryllium, magnesium, and strontium, which are found in smaller quantities.

Alkaline earth metals tend to form oxides with the formula:

• M₂O

• MO

• M₂O₃

• MO₂

Answer explanation

Alkaline earth metals, such as magnesium and calcium, typically form oxides with the formula MO, where M represents the metal. This is due to their +2 oxidation state, resulting in a 1:1 ratio with oxygen.

What is the general oxidation state of alkaline earth metals in their compounds?

• +1

• +2

• +3

• +4

Answer explanation

The general oxidation state of alkaline earth metals, which include elements like magnesium and calcium, is +2 in their compounds. This is because they tend to lose two electrons to achieve a stable electron configuration.

Which of the following is the correct order of increasing atomic size for alkali metals?

• Li < Na < K < Rb < Cs

• Cs < Rb < K < Na < Li

• Na < K < Li < Cs < Rb

• Li < K < Na < Rb < Cs

Answer explanation

The atomic size of alkali metals increases down the group due to the addition of electron shells. Therefore, the correct order of increasing atomic size is Li < Na < K < Rb < Cs.

Electro-negativity of Alkali metals decreases from Li to Cs?

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Answer explanation

Electro-negativity of alkali metals decreases from Li to Cs due to increasing atomic size and shielding effect, which reduces the nucleus's ability to attract bonding electrons.

Ionization energy decreases from top to bottom in s –block elements?

 

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Answer explanation

Ionization energy decreases from top to bottom in s-block elements due to increased atomic size and shielding effect, making it easier to remove the outermost electron.

    Boiling point of halogens increases down the group in the periodic table ?

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Answer explanation

Yes, the boiling point of halogens increases down the group due to the increase in molecular size and mass, leading to stronger van der Waals forces. This results in higher energy required to break these intermolecular forces.