Question

select the subatomic composition of a gold(i) ion (au⁺) with a mass number of 197. refer to a periodic table. 79 protons, 79 neutrons, 78 electrons 78 protons, 118 neutrons, 79 electrons 78 protons, 79 neutrons, 79 electrons 79 protons, 118 neutrons, 78 electrons

Explanation:

Step1: Determine number of protons

Gold (Au) has an atomic number of 79. Atomic number = number of protons, so there are 79 protons.

Step2: Calculate number of neutrons

Mass number = number of protons + number of neutrons. Given mass number = 197 and number of protons = 79, then number of neutrons = 197 - 79=118.

Step3: Determine number of electrons

The ion is $Au^{+}$, which means it has lost 1 electron. Neutral gold has 79 electrons, so the ion has 79 - 1 = 78 electrons.

Answer:

79 protons, 118 neutrons, 78 electrons