Gadolinium (Gd) is element 64 on the periodic table. A sample contains 4.56×1022 atoms of Gd. What amount (mol) of Gd is present in a sample containing 4.56×1022 atoms?

.757 moles of Gd is present in a sample containing 4.56x10^22 atoms of Gd.

Explanation:

Atoms --> Moles

1. Take the given number and put it over 1

(4.56x10^22 atoms/1)

2. Multiply by 6.022x10^23 to go from atoms to moles

(4.56x10^22 atoms/1) (1mol Gd/6.022x10^22 atoms)= .757223513...

3. Round by sigfigs

4.56 has three sigfigs

=.757 mols

the correct option is c.

isotopes refers to different forms of the same element with the same atomic number but different mass number as a result of difference in their neutron numbers. isotopes have different relative atomic mass but share the same chemical properties.