alleryIn the modern periodic table, elements with atomic numbers 11 to 18 are placed in which period?
A3
B1
C2
D4
Answer & Solution
Correct answer: A. 3
1. Period 1 holds atomic numbers 1–2, period 2 holds 3–10.
2. The next period, period 3, holds atomic numbers 11–18.
3. Hence elements 11 to 18 are in period 3.
_Source: RRB Group D CEN-02/2018 PYQ, Q.45._
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