Only two elements are present in:
Correct answer: A. Period 1
- A. Period 1
- B. Period 2
- C. Period 3
- D. Period 4
- E. Period 5
Explanation
Period 1 of the periodic table consists of only two elements: hydrogen and helium. This is because the first electron shell (the 1s orbital) can hold a maximum of two electrons. In contrast, Periods 2 and 3 each have 8 elements, as they include the filling of s and p orbitals. Periods 4 and 5 have even more elements, 18 each, due to the inclusion of the d orbitals. Hence, the correct answer is Period 1, where only two elements are present.
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About s-Block and p-Block Elements
The s and p blocks are studied through their valence-shell configurations, periodic trends and characteristic chemical properties. Work covers the reactions of Group I and Group II elements, the behaviour of Group IV elements, and how atomic size, ionization energy, electronegativity and metallic character change across periods and down groups.
Practise s-Block and p-Block Elements
1,359 free s-Block and p-Block Elements MCQs from Chemistry, each with the correct answer and an explanation. Unlimited attempts, no account needed.
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