Question

1. the species shown below which has 24 neutrons is (3pts) \\(_{24}^{52}\text{cr}\\) \\(_{25}^{55}\text{mn}\\) \\(_{12}^{24}\text{mg}\\) \\(_{21}^{45}\text{sc}\\) \\(_{23}^{47}\text{v}\\)

Explanation:

Step1: Recall neutron count formula

Neutrons = Mass number - Atomic number ($N = A - Z$)

Step2: Calculate neutrons for $\ce{^{52}_{24}Cr}$

$N = 52 - 24 = 28$

Step3: Calculate neutrons for $\ce{^{55}_{25}Mn}$

$N = 55 - 25 = 30$

Step4: Calculate neutrons for $\ce{^{24}_{12}Mg}$

$N = 24 - 12 = 12$

Step5: Calculate neutrons for $\ce{^{45}_{21}Sc}$

$N = 45 - 21 = 24$

Step6: Calculate neutrons for $\ce{^{51}_{23}V}$

$N = 51 - 23 = 28$

Answer:

$\boldsymbol{^{45}_{21}Sc}$