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Chemistry Chapter 4 : Topic 2
Period, Group and Block
1 / 10
An element has the electronic configuration 1s² 2s² 2p⁶ 3s² 3p⁴. By analyzing its configuration, a student concludes that the element lies in Period 3 and belongs to the p-block. Which reasoning best justifies this conclusion?
Reasoning: The period is determined by the highest energy level (n = 3), and the last electron enters the p-subshell, so it is a p-block element.
2 / 10
An element ends its electronic configuration in the subshell 4s¹. A student identifies it as an s-block element in Period 4. What is the most accurate justification?
Reasoning: The last electron enters the s-subshell, so it is s-block, and n=4 indicates Period 4.
3 / 10
An element has configuration [Ne] 3s² 3p⁶. A student states it belongs to Group 18. Which idea best supports this statement?
Reasoning: A full outer shell (ns² np⁶) indicates noble gases in Group 18.
4 / 10
An element has configuration 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁵ 4s¹. A student identifies it as a transition element. Which reasoning is correct?
Reasoning: Presence of partially filled d-orbitals indicates a d-block (transition) element.
5 / 10
An element has its last electron entering the f-subshell. A student predicts it belongs to inner transition elements. What is the best explanation?
Reasoning: Elements with f-subshell filling belong to inner transition series (lanthanides / actinides).
6 / 10
Consider an element with configuration ending in 3p³. A student claims it belongs to Period 3 and p-block. What is the most logical justification?
Reasoning: Period is determined by n=3, & last electron in p-subshell confirms p-block.
7 / 10
An element has configuration [Ar] 4s² 3d¹⁰ 4p². A student identifies it as a p-block element. What supports this classification?
Reasoning: The outermost electrons are in the p-subshell (4p²), so it is p-block.
8 / 10
Why is the periodic table divided into s, p, d, and f blocks based on electronic configuration?
Reasoning: Block classification depends on the subshell into which the last electron enters.
9 / 10
An element has configuration ending in 5d¹. A student concludes it is a d-block element in Period 6. Which statement best supports this?
Reasoning: d-block elements involve d-subshell filling, and period is determined by highest occupied principal shell in configuration context.
10 / 10
A student is given two elements: Element A ends in 2s² and Element B ends in 2p⁵. Which conclusion is correct regarding their block classification?
Reasoning: Block depends on last electron subshell:s → s-block ; p → p-block
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