13. Select three elements that are in the same period of the Periodic Table and arrange these elements in order of increasing electronegativity. 5)K 1) F 2) Se 3) Na 4) Br Answer (score:1):

The correct answer is: 3) Na, 4) Br, 2) Se.<br /><br />Explanation: The elements in the same period of the Periodic Table are K (Potassium), Na (Sodium), F (Fluorine), Se (Selenium), and Br (Bromine). Electronegativity increases from left to right across a period. Therefore, the order of increasing electronegativity is Na, Br, Se.