Atom of seven elementsA,B ,C, D, E,F and G have a differentnumber of electronic shells but havethe same number of electrons in their outermostshells.The element A and C combine with chlorine to form an acidand common salt respectively. The oxide of element A is liquidat room temperatureand is a neutral substancewhile the oxides of theremainingsix elements are basic in nature . Based on the above information, anwerthe followingquestion given ahead : Writethe formulaof the compoundformed by the reaction of the element A with oxygen .

Atom of seven elementsA,B ,C, D, E,F and G have a differentnumber of e

1.	Atom of seven elementsA,B ,C, D, E,F and G have a differentnumber of electronic shells but havethe same number of electrons in their outermostshells.The element A and C combine with chlorine to form an acidand common salt respectively. The oxide of element A is liquidat room temperatureand is a neutral substancewhile the oxides of theremainingsix elements are basic in nature . Based on the above information, anwerthe followingquestion given ahead : Writethe formulaof the compoundformed by the reaction of the element A with oxygen .
Answer» Solution :Since all the seven elementshave same number of electron in their OUTERMOSTSHELLS, this meansthat they belongto the same group. From the availableinformation , it becomesclear that the group of ALKALI metals ( group 1 ) . HYDROGEN (A) is also INCLUDED. The elements presentare : Let us answerthe question asked . The formulaof compound is `H_2O` .