Question

current attempt in progress
complete the following table with the appropriate data for each isotope given (all are neutral atoms):

element	symbol	atomic number	mass number	number of protons	number of neutrons	number of electrons
gold				197
			56			79
						20	18
				58	28

Explanation:

Step1: Recall atomic number and symbol for chlorine

Chlorine has atomic number 17 and symbol Cl. For $^{36}Cl$, mass number is 36. In a neutral atom, number of protons = atomic number = 17, number of neutrons = mass number - number of protons = 36 - 17 = 19, number of electrons = number of protons = 17.

Step2: Recall atomic number and properties for gold

Gold has symbol Au and atomic number 79. Given mass number 197, number of protons = 79, number of neutrons = 197 - 79 = 118, number of electrons = 79.

Step3: Calculate atomic number and other values

Given mass number 56 and number of neutrons 79, number of protons = mass number - number of neutrons = 56 - 79 is not possible. There is likely an error. Assuming the correct data, if we know number of protons, we can find other values. Let's assume the element is iron (Fe) with atomic number 26. Mass number 56, number of protons 26, number of neutrons 56 - 26 = 30, number of electrons 26.

Step4: Determine element from electron - neutron data

Number of electrons 18 means number of protons 18 (neutral atom). Element is argon (Ar). Mass number = number of protons+number of neutrons = 18 + 20 = 38.

Step5: Determine element from proton - mass number data

Number of protons 28 means atomic number 28. Element is nickel (Ni). Mass number 58, number of neutrons = 58 - 28 = 30, number of electrons 28.

Answer:

Element	Symbol	Atomic number	Mass number	Number of protons	Number of neutrons	Number of electrons
Gold	Au	79	197	79	118	79
Iron (assumed)	Fe	26	56	26	30	26
Argon	Ar	18	38	18	20	18
Nickel	Ni	28	58	28	30	28