Atomic structure basics: A neutral atom with atomic number 5 contains how many electrons?

Introduction / Context:
Electronics and materials science rest on atomic structure. The atomic number directly gives the number of protons in the nucleus; neutrality means the number of electrons equals the number of protons. This concept underpins band theory, conductivity, and semiconductor doping.

Given Data / Assumptions:

• Atomic number Z = 5.
• The atom is neutral (no net charge).

Concept / Approach:
Atomic number Z is the count of protons. A neutral atom has total charge zero, so the electron count equals the proton count. Therefore, electrons = Z for a neutral atom. Z = 5 corresponds to boron in the periodic table, which has 5 protons and thus 5 electrons when neutral.

Step-by-Step Solution:

Verification / Alternative check:
Periodic table cross-check: Boron (B) has atomic number 5. Its ground-state electron configuration totals five electrons (1s^2 2s^2 2p^1), matching the conclusion.

Why Other Options Are Wrong:

• 1 or none: Do not match Z = 5 under neutrality.
• Depends on the type of atom: For neutrality, electron count always equals Z, independent of isotope; only ionization changes it.

Common Pitfalls:

• Confusing atomic number with mass number; mass number includes neutrons.

Final Answer:
5