Classification Of Elements And Periodicity In Properties

Step 1: Understand electronegativity trend.
Electronegativity decreases down a group due to increase in atomic size and shielding effect.
Step 2: Analyze the given elements.
All the given elements belong to Group 15 of the periodic table. As we move down the group from nitrogen to bismuth, electronegativity decreases.
Step 3: Conclusion.
Bismuth is the lowest in the group and hence has the lowest electronegativity among the given options.

Atomic size decreases as we move from left to right across a period in the periodic table because the effective nuclear charge increases, pulling the electrons closer to the nucleus. Thus, the correct order of increasing atomic size is: Thus, the atomic size decreases from sodium (Na) to magnesium (Mg) to aluminum (Al).

Understanding Electronegativity:
Electronegativity is the tendency of an atom to attract electrons in a chemical bond. It is influenced by atomic size and the effective nuclear charge (Z_eff).

In the periodic table:
• Electronegativity increases across a period (left to right).
• Electronegativity decreases down a group (top to bottom).

Oxygen vs Chlorine:
- Oxygen is in Period 2, Group 16, while Chlorine is in Period 3, Group 17.
- Oxygen has a smaller atomic radius compared to chlorine.
- Due to this, oxygen's valence electrons are closer to the nucleus and experience a stronger effective nuclear charge.
- Hence, oxygen pulls shared electrons more strongly than chlorine.

Correct Reason:
Oxygen has smaller size and a greater effective nuclear charge, making it more electronegative than chlorine.

Final Answer: Option 2: Oxygen has smaller size and more effective nuclear charge

Electronegativity generally increases as you move across a period from left to right and decreases down a group. Based on the electronegativity values from the Pauling scale, the order is: Therefore, the correct order is F > O > N > Cl.

The electron configuration of each element in its ground state: - Neon (Ne): 1s 2s 2p → Complete octet in the outermost shell. - Helium (He): 1s → Complete duet in the outermost shell. - Oxygen (O): 1s 2s 2p → Not completely filled in the 2p orbital (can hold 6 electrons). - Argon (Ar): 1s 2s 2p 3s 3p → Complete octet in the outermost shell. Answer: Oxygen does not have a completely filled outermost shell, so the correct answer is option (3).