Question

select the correct answer. what can you say about a calcium atom by looking at the symbol $_{20}^{44}ca$? a. a calcium atom has 44 neutrons and 20 electrons. b. a calcium atom has 20 protons and 24 electrons. c. a calcium atom has 64 protons and 20 neutrons. d. a calcium atom has 20 protons and 24 neutrons. e. a calcium atom has 20 protons and 44 neutrons.

Explanation:

Step1: Identify atomic number and mass number

In the symbol $_{20}^{44}Ca$, the bottom - number (20) is the atomic number ($Z$), which represents the number of protons. The top - number (44) is the mass number ($A$), which is the sum of protons and neutrons.

Step2: Calculate the number of neutrons

The formula to find the number of neutrons ($N$) is $N=A - Z$. Given $A = 44$ and $Z = 20$, then $N=44 - 20=24$.

Answer:

D. A calcium atom has 20 protons and 24 neutrons.