How many atoms of potassium are in 4.25 g of potassium
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1.00 x 10^26 atoms K

Explanation:

Convert from grams to moles (using K molar mass)

K molar mass = 39.098 g/mol

4.25 g K x 39.098 mols K / 1 g K

[grams cancel out]

= 166.1665 mols K

Convert from moles to atoms (using Avogadro's number)

Avogadro's number = 6.0221 x 10^23

166.1665 mols K x 6.0221 x 10^23 atoms K / 1 mols K

[mols cancel out]

= 1.00067128 x 10^26 atoms

[with proper significant digits]

= 1.00 x 10^26 atoms K

indium, and thallium have three electrons i think