Classification of Elements & Periodicity in Properties Quiz - ICSE Class 11 Chemistry
Free practice quiz: Classification of Elements & Periodicity in Properties (ICSE Class 11 Chemistry). 39 multiple-choice questions with answers and explanations. Play online, no sign-up needed.
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Which of the following statements is INCORRECT regarding the modern periodic law?
- The physical and chemical properties of elements are periodic functions of their atomic numbers.
- The position of an element in the periodic table is determined by its atomic number.
- Elements in the same group have similar chemical properties due to the same number of valence electrons.
- The periodic law states that the properties of elements are periodic functions of their atomic masses.
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Answer: D. The periodic law states that the properties of elements are periodic functions of their atomic masses.
The modern periodic law, formulated by Moseley, states that the properties of elements are periodic functions of their atomic numbers, not atomic masses. The atomic number determines the electronic configuration, which in turn dictates the chemical behavior of an element.
Which pair of elements has similar chemical properties?
- Na and Mg
- Li and Na
- Be and B
- C and N
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Answer: B. Li and Na
Elements in the same group of the periodic table have similar chemical properties because they have the same number of valence electrons. Lithium (Li) and Sodium (Na) are both alkali metals (Group 1) and have one valence electron (ns¹), leading to similar chemical behaviors.
The element with the electronic configuration [Xe] 4f⁷ 6s² belongs to which block of the periodic table and what is its group name?
- f-block, Lanthanoid
- d-block, Transition metal
- p-block, Halogen
- s-block, Alkali metal
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Answer: A. f-block, Lanthanoid
The electronic configuration shows that the differentiating electrons are entering the 4f subshell. Elements where the last electron enters the f-orbital are called f-block elements. Specifically, the configuration [Xe] 4f⁷ 6s² corresponds to Europium (Eu), which is a Lanthanoid.
The elements of Group 17 are called:
- Alkali metals
- Alkaline earth metals
- Halogens
- Noble gases
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Answer: C. Halogens
Group 17 elements in the periodic table are known as Halogens. Examples include Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I), and Astatine (At). Alkali metals are in Group 1, Alkaline earth metals are in Group 2, and Noble gases are in Group 18.
Which of the following statements regarding the placement of elements in the periodic table is correct?
- Hydrogen is placed in Group 1 because it has one valence electron, but it also shares some properties with Group 17 elements.
- Helium, with electron configuration 1s², is placed in Group 18 due to its chemical inertness, despite having only 2 electrons.
- Elements with similar electronic configurations of their outermost shells are placed in the same group.
- All of the above
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Answer: D. All of the above
Statement 1 is correct: Hydrogen has one valence electron like alkali metals (Group 1) and also resembles halogens (Group 17) by needing one electron to achieve a stable configuration. Statement 2 is correct: Helium's inertness and filled valence shell (1s²) dictate its placement with noble gases in Group 18. Statement 3 is correct: The periodic law states that elements with similar valence electron configurations exhibit similar chemical properties and are placed in the same group.