The electron configuration of Ba2+ is isoelectronic with the noble gas: Kr. 65. Which element has the highest first ionization potential: fluorine. 66. Which element is the most electronegative one: a. As. 67. Lithophiles are found primarily in the Earth’s crust in silicate minerals; examples include Li, Mg, Ti, Al, and Cr (as their cations). 68. Which of the following is an example of a metalloid? b. Sn. 69. Which elements of the d-block can achieve the group oxidation state? Elements in Groups 9 to 10. 70. Which of the following oxides has only acidic character: MgO.
The Correct Answer and Explanation is:
Let’s go through each of the questions one by one:
65. The electron configuration of Ba²⁺ is isoelectronic with the noble gas: Kr.
- Explanation: The electron configuration of neutral Ba (Barium) is [Xe] 6s². When Ba loses two electrons to form Ba²⁺, the configuration becomes [Xe], which is exactly the same as the electron configuration of krypton (Kr), a noble gas. Thus, Ba²⁺ is isoelectronic with Kr.
66. Which element has the highest first ionization potential: fluorine?
- Explanation: Ionization potential refers to the energy required to remove an electron from an atom in its gaseous state. Fluorine has the highest first ionization potential among the elements due to its small atomic size and high effective nuclear charge, making it harder to remove an electron. Fluorine is one of the most electronegative elements as well, and its high ionization energy reflects this.
67. Which element is the most electronegative one: As?
- Explanation: Fluorine (F), not arsenic (As), is the most electronegative element. Electronegativity is the ability of an atom to attract electrons when bonded to another atom. Fluorine is the most electronegative element on the periodic table, with an electronegativity value of 3.98 on the Pauling scale, whereas arsenic has a value of 2.18.
68. Lithophiles are found primarily in the Earth’s crust in silicate minerals; examples include Li, Mg, Ti, Al, and Cr (as their cations).
- Explanation: Lithophiles are elements that tend to bond with oxygen and are found predominantly in the Earth’s crust. These elements often form silicates or oxides. Examples include Li (Lithium), Mg (Magnesium), Ti (Titanium), Al (Aluminum), and Cr (Chromium), all of which form stable cations like Li⁺, Mg²⁺, Ti⁴⁺, Al³⁺, and Cr³⁺.
69. Which of the following is an example of a metalloid? b. Sn
- Explanation: Tin (Sn) is actually a metal, not a metalloid. A metalloid is an element that has properties between metals and nonmetals. Examples of metalloids include elements like Si (Silicon), B (Boron), and Ge (Germanium), which have semi-conductive properties.
70. Which elements of the d-block can achieve the group oxidation state? Elements in Groups 9 to 10.
- Explanation: The elements in Groups 9 and 10 of the d-block (Transition metals) can achieve the group oxidation state, particularly +1 and +2 oxidation states. For example, elements like Ni (Nickel), Pd (Palladium), Pt (Platinum), and Ir (Iridium) in Group 10 can form various oxidation states, including the +2 oxidation state. However, the group oxidation state generally refers to the most stable and common oxidation state for the elements in that group.
71. Which of the following oxides has only acidic character: MgO.
- Explanation: MgO is an oxide of a metal (Magnesium) and behaves basic in nature. When it reacts with water, it forms Mg(OH)₂, a basic solution. In contrast, acidic oxides typically come from non-metals, like CO₂ (carbon dioxide) or SO₂ (sulfur dioxide). Therefore, the correct answer for an oxide with only acidic character would not be MgO but rather an oxide like SO₂.
In summary:
- Ba²⁺ is isoelectronic with Kr.
- Fluorine has the highest first ionization potential.
- Fluorine is the most electronegative element, not arsenic.
- Lithophiles include elements like Li, Mg, Ti, Al, and Cr.
- Tin (Sn) is a metal, not a metalloid.
- Transition metals in Groups 9 and 10 can achieve various oxidation states.
- MgO is basic, not acidic.
