9. Select three elements that are in the same period of the Periodic Table and arrange these elements in order.of increasing.electronegativity. 1) (2) Be (3)Mg 4) Cl 5) Li Answer (score: #):

## Step 1<br />The Periodic Table is organized into periods (rows) and groups (columns). Elements in the same period have the same number of electron shells. Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons. In the Periodic Table, electronegativity increases from left to right across a period.<br /><br />## Step 2<br />The elements given in the question are Be (Beryllium), Mg (Magnesium), Cl (Chlorine), and Li (Lithium). These elements are all in the same period of the Periodic Table.<br /><br />## Step 3<br />To arrange these elements in order of increasing electronegativity, we need to consider their positions in the Periodic Table. Lithium (Li) is the furthest to the left and therefore has the lowest electronegativity. Magnesium (Mg) is to the right of Lithium but to the left of Beryllium (Be), so it has a higher electronegativity than Lithium but lower than Beryllium. Beryllium (Be) is to the right of Magnesium, so it has a higher electronegativity than both Lithium and Magnesium. Chlorine (Cl) is the furthest to the right among these elements, so it has the highest electronegativity.