Question

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

Answer 1

1.  K

2.Be  AND  Ca

3. KCL