Electronegativities of group 4 elements decrease with the rise of atomic number but not a regular manner. Why?

due to the filling of the d-orbital

due to the filling of the s-orbital

due to the filling of the p-orbital

due to the filling of the d-orbital

due to the filling of the f-orbital

As we move down the group from C to Pb, the melting points as well as boiling points generally decrease, although the decrease is not in a regular order. This decrease in melting points as well as in boiling points indicates that

inter-atomic forces decrease in the same direction

inter-atomic forces increase in the same direction

atomic number increase down the group

inter-atomic forces first decrease then increase in the same direction

inter-atomic forces decrease in the same direction

Quiz Ch. 13 Topic 13.4

1.

Electronegativities of group 4 elements decrease with the rise of atomic number but not a regular manner. Why?
- A.
  
  Due to the filling of the s-orbital
- B.
  
  Due to the filling of the p-orbital
- C.
  
  Due to the filling of the d-orbital
- D.
  
  Due to the filling of the f-orbital
Correct Answer
C. Due to the filling of the d-orbital

Explanation
The electronegativities of group 4 elements decrease with the rise of atomic number due to the filling of the d-orbital. As the atomic number increases, additional electrons are added to the d-orbital, which is further from the nucleus compared to the s-orbital. This results in a weaker attraction between the electrons and the nucleus, leading to a decrease in electronegativity.

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2.

As we move down the group from C to Pb, the melting points as well as boiling points generally decrease, although the decrease is not in a regular order. This decrease in melting points as well as in boiling points indicates that
- A.
  
  Inter-atomic forces increase in the same direction
- B.
  
  Atomic number increase down the group
- C.
  
  Inter-atomic forces first decrease then increase in the same direction
- D.
  
  Inter-atomic forces decrease in the same direction
Correct Answer
D. Inter-atomic forces decrease in the same direction

Explanation
As we move down the group from C to Pb, the inter-atomic forces between the atoms in the elements decrease. This is reflected in the decrease in melting points and boiling points. The decrease in inter-atomic forces can be attributed to the increase in atomic size and the increase in the number of electron shells as we move down the group. Therefore, the correct answer is that inter-atomic forces decrease in the same direction.

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3.

Identify the allotropes of carbon.
- A.
  
  Lead
- B.
  
  Graphite
- C.
  
  Diamond
- D.
  
  Both B and C
Correct Answer
D. Both B and C

Explanation
Both graphite and diamond are allotropes of carbon. Allotropes are different forms of the same element, in this case, carbon, that have different physical and chemical properties. Graphite is a soft, black, and slippery substance with a layered structure, while diamond is a hard, transparent crystal with a tetrahedral arrangement of carbon atoms. Both graphite and diamond are made up of carbon atoms but have different arrangements, resulting in their distinct properties. Therefore, the correct answer is both B (graphite) and C (diamond).

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4.

Diamond has a three-dimensional structure of carbon atoms each joined covalently to ----------- other atoms
- A.
  
  2
- B.
  
  4
- C.
  
  6
- D.
  
  8
Correct Answer
B. 4

Explanation
Diamond has a three-dimensional structure of carbon atoms each joined covalently to four other atoms. In a diamond, each carbon atom forms four strong covalent bonds with its neighboring carbon atoms, resulting in a rigid and stable structure. This arrangement allows diamond to have a high melting point and hardness, making it one of the hardest substances known.

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5.

The common allotrope of tin is
- A.
  
  Alpha tin
- B.
  
  Beta tin
- C.
  
  Grey tin
- D.
  
  Golden tin
Correct Answer
B. Beta tin

Explanation
Beta tin is the correct answer because it is the most stable allotrope of tin at temperatures below 13.2 degrees Celsius. It has a metallic, crystalline structure and is commonly referred to as "white tin." Alpha tin, on the other hand, is the allotrope of tin that is stable at temperatures above 13.2 degrees Celsius. Grey tin and golden tin are not commonly used terms to describe the allotropes of tin.

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6.

We compare the stability of M2+ and M4+ cations of Ge, Sn and Pb, we find that their stability is in the order
- A.
  
  Ge2+>Ge4+; Sn2+>Sn4+; Pb2+
- B.
  
  Ge2+Sn4+; Pb2+>Pb4+
- C.
  
  Ge2+
- D.
  
  Ge2+Pb4+
Correct Answer
D. Ge2+Pb4+

Explanation
The correct answer is Ge2+Pb4+. This is because when comparing the stability of M2+ and M4+ cations of Ge, Sn, and Pb, Ge2+ is more stable than Ge4+, and Pb4+ is more stable than Pb2+. Therefore, the correct order of stability is Ge2+Pb4+.

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7.

NaOH + CO ---->
- A.
  
  NaOH + CO₂
- B.
  
  HCONa
- C.
  
  HCOONa
- D.
  
  NaCOOH
Correct Answer
C. HCOONa

Explanation
When sodium hydroxide (NaOH) reacts with carbon monoxide (CO), it forms sodium formate (HCOONa). This reaction occurs by the exchange of atoms, where the sodium from NaOH replaces the hydrogen in CO, resulting in the formation of HCOONa. Sodium formate is a salt that is commonly used in various industries, including textile, leather, and paper manufacturing.

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8.

NaOH + CO_2------>
- A.
  
  NaHCO₃
- B.
  
  Na₂CO₃+ H₂O
- C.
  
  CH₃COONa
- D.
  
  NaO + CH₄
Correct Answer
A. NaHCO₃

Explanation
NaOH reacts with CO2 to form NaHCO3. This is a common reaction known as the neutralization of an acid with a base. NaOH is a strong base and CO2 is an acidic gas. When they react, the CO2 is neutralized by the NaOH, resulting in the formation of NaHCO3, which is sodium bicarbonate. This reaction is commonly used in industries and laboratories to produce sodium bicarbonate, which has various applications including as a leavening agent in baking and as an antacid.

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9.

PbO₂ + 2NaOH --------->
- A.
  
  Na₂PbO₃ + H₂
- B.
  
  Na₂PbO2 + H₂O
- C.
  
  Na₂PbO + H₂O
- D.
  
  Na₂PbO₃ + H₂O
Correct Answer
D. Na₂PbO₃ + H₂O

Explanation
When PbO2 reacts with 2NaOH, it forms Na2PbO3 and H2O.

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10.

H₂O + CO_2----->
- A.
  
  H₂CO₃
- B.
  
  2HCO₃
- C.
  
  H₂+ 2CO
- D.
  
  H₂CO2
Correct Answer
A. H₂CO₃

Explanation
The balanced chemical equation for the reaction given is H2O + CO2 → H2CO3. This means that when water (H2O) reacts with carbon dioxide (CO2), it forms carbonic acid (H2CO3).

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Quiz Ch. 13 Topic 13.4

Electronegativities of group 4 elements decrease with the rise of atomic number but not a regular manner. Why?

As we move down the group from C to Pb, the melting points as well as boiling points generally decrease, although the decrease is not in a regular order. This decrease in melting points as well as in boiling points indicates that

Identify the allotropes of carbon.

Diamond has a three-dimensional structure of carbon atoms each joined covalently to ----------- other atoms

The common allotrope of tin is

We compare the stability of M2+ and M4+ cations of Ge, Sn and Pb, we find that their stability is in the order

NaOH + CO ---->

NaOH + CO2------>

PbO2 + 2NaOH --------->

H2O + CO2----->

NaOH + CO_2------>

PbO₂ + 2NaOH --------->

H₂O + CO_2----->