Question

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).

Answer 1

1) 19K
2)4BE and 20ca
3)19K is potassium. Element X is chlorine. Atomic number-17.The compound formed isKCl (potassium chloride)