How many atoms are in 25.8 grams of Hg (mercury)

7.74568E22 or 7.74568 * 10^22 atoms

Explanation:

To find this, we first must find the moles of mercury in 25.8 grams. Since the molar mass of Hg is 200.59, we can find moles of Hg from 25.8 / 200.59 = 0.1286

To find the amount of atoms, we must multipy the amount of moles by Avagadro's number.

.1286 * 6.02214076 * 10²³ is 7.74568E22 or 7.74568 * 10^22 atoms

indium, and thallium have three electrons i think