Question

1. which of these particles have the heaviest mass? select two correct answers.

₁¹h
₄⁹be
₂⁴he
₋₁⁰e
₈¹⁶o

Explanation:

Step1: Recall mass of particles

The mass of a particle (atom) is related to its atomic mass number (the superscript in the symbol). The atomic mass number is the sum of protons and neutrons in the nucleus.

• For $\ce{_1^1H}$: Mass number = 1.
• For $\ce{_4^9Be}$: Mass number = 9.
• For $\ce{_2^4He}$: Mass number = 4.
• For $\ce{_{-1}^0e}$ (electron): Mass is much smaller (negligible compared to atomic nuclei, mass number 0 as it has no protons/neutrons in nucleus).
• For $\ce{_8^{16}O}$: Mass number = 16.

Step2: Compare mass numbers

Higher mass number generally means heavier mass (since protons and neutrons have significant mass, and electrons have negligible mass compared to them). Among the given, $\ce{_8^{16}O}$ (mass number 16) and $\ce{_4^9Be}$ (mass number 9) have higher mass numbers than $\ce{_1^1H}$ (1), $\ce{_2^4He}$ (4), and the electron (mass number 0). So the two heaviest are $\ce{_4^9Be}$ and $\ce{_8^{16}O}$.

Answer:

B. $\boldsymbol{_4^9Be}$, E. $\boldsymbol{_8^{16}O}$ (assuming options are labeled as A: $\ce{_1^1H}$, B: $\ce{_4^9Be}$, C: $\ce{_2^4He}$, D: $\ce{_{-1}^0e}$, E: $\ce{_8^{16}O}$)