Question

question 7. which of the following elements are less electronegative than magnesium (mg)? select all that apply:
□ aluminium (al)
□ calcium (ca)
□ francium (fr)
□ oxygen (o)
□ sodium (na)
□ barium (ba)

Explanation:

To determine which elements are less electronegative than magnesium (Mg), we use the electronegativity trend: electronegativity generally increases across a period (left to right) and decreases down a group (top to bottom) in the periodic table. Magnesium is in Group 2, Period 3.

Step 1: Analyze each element

• Aluminium (Al): Period 3, Group 13. To the right of Mg in the same period. Electronegativity increases across a period, so Al (≈1.61) > Mg (≈1.31). Eliminate.
• Calcium (Ca): Group 2, Period 4. Below Mg in the same group. Electronegativity decreases down a group, so Ca (≈1.00) < Mg (≈1.31). Include.
• Francium (Fr): Group 1, Period 7. Far below and left of Mg. Electronegativity decreases down a group and left across a period, so Fr (≈0.7) < Mg. Include.
• Oxygen (O): Period 2, Group 16. Far to the right of Mg. Electronegativity increases across periods, so O (≈3.44) > Mg. Eliminate.
• Sodium (Na): Period 3, Group 1. To the left of Mg in the same period. Electronegativity increases across a period, so Na (≈0.93) < Mg (≈1.31). Include.
• Beryllium (Be): Group 2, Period 2. Above Mg in the same group. Electronegativity increases up a group, so Be (≈1.57) > Mg (≈1.31). Eliminate.

Answer:

The elements less electronegative than magnesium are:

• Calcium (Ca)
• Francium (Fr)
• Sodium (Na)