Answer:
Hydrogen
Explanation:
The third period contains eight elements: sodium, magnesium, aluminium, silicon, phosphorus, sulfur, chlorine, and argon. The first two, sodium and magnesium, are members of the s-block of the periodic table, while the others are members of the p-block.
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Period 3 element.
Hydrogen Francium
Radium
Actinium
Rutherfordium
Dubnium
