ANATOMY

Detailed explanation-1: -Statement R: The oxygen atom has six electrons, it shows a valency of 2.

Detailed explanation-2: -Therefore, the second-row element that has 6 valence electrons and valency of 2 is oxygen.

Detailed explanation-3: –2 is the valency in which the total number of electrons in the outermost shell is equal to 6. For example, the element sulfur contains 6 valence electrons in the outer shell, which will gain two 2 electrons, and attain a valency of-2.

Detailed explanation-4: -Therefore, it is very reactive and gives up electrons in chemical reactions. It is likely to react with an element with six valence electrons that “wants” to gain two electrons. This would be an element in group 6, such as oxygen.