Question

question 7. four elements are shown in the diagram below. based on their positions on the periodic table and the periodic trend of electronegativity, identify the element with the lowest electronegativity.

periodic table diagram

element 1
element 2
element 3
element 4

Explanation:

Step1: Recall Electronegativity Trend

Electronegativity decreases down a group and increases across a period (from left to right) in the periodic table.

Step2: Analyze Element Positions

- Element 1: Lower left (group 1, period 5) – far left and lower period.
- Element 2: Middle (group 6, period 4) – middle group, higher period than 1? No, period 4 vs 5 for 1? Wait, no: period 5 is lower (more down) than period 4. Wait, period number increases as we go down. So element 1 is in period 5 (row 5), group 1. Element 2: period 4, group 6. Element 3: period 6, group 15? Wait, no, the grid: rows are periods (1 - 7), columns groups (1 - 18). So element 1: row 5 (period 5), column 1 (group 1). Element 2: row 4 (period 4), column 6 (group 6). Element 3: row 6 (period 6), column 15? Wait, no, column 15 is group 15? Wait, the grid: column 1 (group 1), column 2 (group 2), then columns 3 - 12 (transition), then 13 - 18 (groups 13 - 18). So element 3: row 6, column 15? Wait, no, the labels: element 1 is row 5, column 1 (group 1, period 5). Element 2: row 4, column 6 (group 6, period 4). Element 3: row 6, column 15? Wait, no, column 15 is group 15? Wait, element 4: row 3, column 16 (group 16, period 3).

Now, electronegativity: group 1 (alkali metals) have low electronegativity. Down a group (period increases), electronegativity decreases. So group 1: Li (period 2), Na (3), K (4), Rb (5), Cs (6). So Cs (period 6, group 1) is lowest in group 1. But element 1 is period 5, group 1; element 3 is period 6, group 15? Wait, no, wait the element positions: element 1 is group 1, period 5. Element 3: group 15, period 6. Element 2: group 6, period 4. Element 4: group 16, period 3.

Wait, group 1 elements (alkali metals) have lower electronegativity than non - metals (groups 6,15,16). Now, within group 1: as period increases (down the group), electronegativity decreases. So element 1 is period 5, group 1; if there was a period 6, group 1 element, it would be lower, but element 1 is group 1, which is lower than group 6,15,16. Wait, but element 1 is in group 1 (alkali metal), which has very low electronegativity. Let's check again:

- Group 1 (alkali) < group 6 (chalcogens) < group 15 (pnictogens) < group 16 (chalcogens? No, group 16 is more electronegative than group 15? Wait, group 16 (O, S, Se, Te) are more electronegative than group 15 (N, P, As, Sb, Bi).

So element 1: group 1 (lowest group electronegativity), period 5. Element 2: group 6, period 4. Element 3: group 15, period 6. Element 4: group 16, period 3.

Now, compare group 1 (element 1) with others: group 1 has lower electronegativity than groups 6,15,16. Now, within group 1, down the group (period increases), electronegativity decreases. So element 1 is period 5, group 1. If there was a period 6, group 1 element, it would be lower, but element 1 is group 1, which is the lowest group for electronegativity. Wait, but element 1 is in group 1, which is the leftmost group, and lower period (wait, period 5 is lower than period 6? No, period 6 is lower (more down) than period 5. Wait, period 1 is top, period 7 is bottom. So period 5 is above period 6. So element 1: period 5 (row 5), element 3: period 6 (row 6). Wait, I made a mistake: row 5 is above row 6. So period 5 is row 5, period 6 is row 6 (more down). So element 1: period 5, group 1. Element 3: period 6, group 15. So group 1 (element 1) is leftmost, and period 5 (above period 6, but group 1 has lower electronegativity than group 15. Wait, no: electronegativity in group 1: as period increases (down), electronegativity decreases. So Li (period 2) < Na (3) < K (4) < Rb (5) < Cs (6). So Cs (period 6, group 1) is lower than Rb (period 5, group 1). But in our case, element 1 is period 5, group 1 (Rb - like), element 3 is period 6, group 15 (Sb or Bi - like). Bi (period 6, group 15) has electronegativity ~2.0, Rb (period 5, group 1) ~0.8, Cs (period 6, group 1) ~0.7. Wait, but element 1 is period 5, group 1 (Rb), element 3 is period 6, group 15 (Bi). So Rb (0.8) vs Bi (2.0): Rb is lower. But wait, element 1 is group 1, which is the lowest possible group for electronegativity (since group 1 is leftmost, and electronegativity increases right). So among the four, element 1 is in group 1 (lowest electronegativity group) and lower period (wait, no, period 5 is above 6, but group 1 has lower electronegativity than group 6,15,16. So element 1 (group 1, period 5) has lower electronegativity than element 2 (group 6, period 4), element 3 (group 15, period 6), and element 4 (group 16, period 3).

Step3: Confirm the Lowest

Since element 1 is in group 1 (lowest electronegativity group) and relatively low period (but even if period 5, group 1 is more left and lower in group 1 trend), it has the lowest electronegativity.

Answer:

Element 1