Hello there!
<span> Use Avogadro's number, 1 mol = 6.02 x 10^23 atoms.
</span>Convert atoms to moles and you get:
<span>9.97x10^(-15) moles Co
</span>
Hope This Helps You!
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Molar mass is the mass of a given substance divided by the amount of that substance, measured in g/mol.
Answer:
Selenium
Explanation:
Oxygen is present in the group sixteen.
This group consist of oxygen, sulfur, selenium, tellurium and polonium.
All of these have same number of valance electrons thus they show similar properties.
From the given list of elements only selenium is belong to oxygen family thus it has properties similar to the oxygen.
Electronic configuration of oxygen:
O = [He] 2s² 2p⁴
Electronic configuration of selenium:
Se = [Ar] 3d¹⁰ 4s² 4p⁴
While aluminium, boron and phosphorus are belongs to other groups that's why their properties are not similar to the phosphorus.
phosphorus is present in group 15.
Boron and aluminium are present in group 13.