Question

fill in the missing information:

symbol	atom or ion? (check all that apply)	number of protons	number of electrons
ru	☐ neutral atom ☐ cation ☐ anion	☐	☐
☐	☐ neutral atom ☐ cation ☐ anion	9	10

Explanation:

Step1: Analyze \( \text{Mg}^{2+} \)

• Atom or ion?: \( \text{Mg}^{2+} \) has a positive charge, so it's a cation (not neutral atom or anion).
• Protons: Atomic number of Mg is 12, so protons = 12.
• Electrons: For \( \text{Mg}^{2+} \), electrons = protons - charge = \( 12 - 2 = 10 \).

Step2: Analyze \( \text{Ru} \)

• Atom or ion?: Ru is a neutral atom (no charge, so not cation/anion).
• Protons: Atomic number of Ru is 44, so protons = 44.
• Electrons: In neutral atom, electrons = protons = 44.

Step3: Analyze the last row

• Protons = 9: Element with atomic number 9 is F (fluorine).
• Electrons = 10, protons = 9: Charge = protons - electrons = \( 9 - 10 = -1 \), so it's \( \text{F}^- \) (anion, not neutral atom/cation).

Answer:

symbol	atom or ion? (check all that apply)	number of protons	number of electrons
\( \text{Ru} \)	neutral atom	44	44
\( \text{F}^- \)	anion	9	10