Question

if R is the symbol of an element in the third period of mandeleev periodic table then what is the formula of its oxide

Answer 1

sodium oxide nd its formula is na2o

Answer 2

If R is the symbol of an element in the third period of Mendeleev's periodic table then the formula of its oxide is R₂O₃.

• The elements belonging to the third period have the general electronic configuration as ns²np¹.
• Hence, they have three valence electrons in their valence shells.
• They can lose these three electrons to have +3 oxidation state and attain noble gas configuration.
• Oxygen belongs to group 16 and has the electronic configuration as 1s²2s²2p⁴. Therefore, it requires 2 electrons to become inert.
• Therefore, the element R loses 3 electrons and O gains two electrons and form R₂O₃ (cross multiplying the oxidation states).