CBSC Session 2022-23.
Sample Papers of Class 10th, Science.
NCERT Important Questions of Class 10th Science.
NCERT Science Solutions of Class 10th.
NCERT book extra Questions.
CBSC Board and other State board.
Write the number of periods the Modern Periodic Table has. State the changes in valency and metallic character of elements as we move from left to right in a period. Also state the changes, if any, in the valency and atomic size of elements as we move down a group
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. No. of periods: 7
. Valency across a period increases from 1 to 4, then decreases from 4 to zero.
. Metallic character of elements across a period decreases.
. Valency down a group remains the same.
. Atomic size of elements down a group increases.