A. Elements in the same period have the same number of valence electrons
B. The valence electrons of the elements in the same period increase progressively across the period
C. Elements in the same group have the same number of electron shells
D. The non-metallic properties of the elements tend to decrease across each period
Correct Answer:
Option B – Elements in the same period have the same number of valence electrons
Explanation
The valence electrons refer to the number of electrons in the outer shell. Across a period (horizontal row), the valence electron increases.
