Question

this is a bohr model of an atom or ion. select the nuclear notation that represents this atom or ion. refer to a periodic table.

Explanation:

Step1: Count Protons (Atomic Number, \( Z \))

Protons (orange \( + \)) in the nucleus: \( Z = 12 \) (matches Mg, \( Z=12 \); eliminates Ca, \( Z=20 \)).

Step2: Count Neutrons (Mass Number, \( A \))

Neutrons (dark circles) in the nucleus: \( 12 \) (since \( A = \text{protons} + \text{neutrons} = 12 + 12 = 24 \)).

Step3: Identify Nuclear Notation

Nuclear notation is \( \ce{^{A}_{Z}X} \). For Mg (\( Z=12 \), \( A=24 \)), this is \( \ce{^{24}_{12}Mg} \).

Answer:

\( \boldsymbol{^{24}_{12}\text{Mg}} \) (or the option labeled \( \boldsymbol{^{24}_{12}\text{Mg}} \) among the choices)