From the following elements : 4Be; 9F; 19K; 20Ca (i) Select the element having one electron is the outermost shell. (ii) two elements of the same group. Write the formula of and mention the nature of the compound formed by the union of 19K and element X(2, 8, 7).



I) 19 K has one electron in its outermost shell
ii)4 Be and 9 F r elements belonging to the same group
X(2,8,7) is chlorine and the elemnt formed by 19 K and 17 Cl is KCl