Question

4Be, 9F, 14Si , 19K , 20Ca. 1) select the elements that has one electron in the outermost shell and write its electronic configuration. 2) select two elements that belong to the some period. which one of the two has bigger atomic size ? 3) select two element that belong to the some group . give reasons for your answer.

Answer 1

K -2,8,8,1
2.  Be AND F
AND K AND Ca.
3. Be AND Ca