Multiple choice

Which of the following is not included in 's' block?

  1. Cs

  2. Mg

  3. Ca

  4. He
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Helium (He) is a noble gas with electron configuration 1s², placing it in the p-block of the periodic table (Group 18). While it fills the 1s orbital, helium is classified with other noble gases due to its similar chemical properties. Cs, Mg, and Ca are all s-block elements - Cs is in Group 1 (alkali metals) while Mg and Ca are in Group 2 (alkaline earth metals).

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