Which of the following statements is correct about the periodic table?

Analysis of the Question

This question tests your understanding of the trends and organizational principles of the Periodic Table. To solve this, we need to evaluate how electron configuration determines an element's position (Group and Period) and how properties change as you move across a period.

Concept Explanation

1. Groups (Vertical Columns): Elements in the same group have the same number of valence electrons (electrons in the outermost shell). This is why they exhibit similar chemical properties.
2. Periods (Horizontal Rows): Elements in the same period have the same number of electron shells.
3. Trends across a Period: As you move from left to right across a period: • The number of valence electrons increases by one for each subsequent element. • The atomic radius generally decreases. • Metallic character decreases, and non-metallic character increases.

Step-by-Step Evaluation

• Option A: Incorrect. Elements in the same period have the same number of electron shells, not the same group.
• Option B: Incorrect. Non-metallic properties actually increase across a period (from left to right, elements go from metals to metalloids to non-metals).
• Option C: Incorrect. Elements in the same group have the same number of valence electrons, not the same period.
• Option D: Correct. As you move across a period (e.g., from Lithium to Neon in Period 2), each element adds one proton to the nucleus and one electron to the valence shell. Therefore, the number of valence electrons increases progressively (1, 2, 3, 4, 5, 6, 7, 8).

Conclusion

Exam Tip

Remember the mnemonic: "G-V-P-S"

• Group = Valence electrons (same)
• Period = Shells (same)

This simple trick will help you avoid mixing up the definitions of groups and periods during your JAMB exam!