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Question
Observe the periodic table given below and write the answers of the questions.

- Write the name and valencies of the elements in 3rd row.
- Classify the elements in this row as metal, nonmetal and metalloids.
- Which block does nonmetals belong to?
- Write name of any two metalloid elements.
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Solution
- The elements in the third period are Sodium, Magnesium, Aluminium, Silicon, Phosphorus, Sulphur, Chlorine and Argon. Their valencies are 1, 2, 3, 4, 3, 2, 1 and 0, respectively.
- Sodium (Na), Magnesium (Mg) and Aluminium (Al) are metals. Silicon (Si) is a metalloid. Phosphorus (P), Sulphur (S), Chlorine (Cl) and Argon (Ar) are nonmetals.
- Nonmetals belong to the p-block.
- Two metalloid elements: Silicon and Germanium.
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