Answer
See explanation
Work Step by Step
a. $K_2Cr_2O_7$
K (potassium): 2
Cr (chromium): 2
O (oxygen): 7
Total atoms per formula unit: 2 + 2 + 7 = 11
b. $C_5H_8NNaO_4$
C (carbon): 5
H (hydrogen): 8
N (nitrogen): 1
Na (sodium): 1
O (oxygen): 4
Total atoms per formula unit: 5 + 8 + 1 + 1 + 4 = 19
c. $C_{10}H_{16}N_2O_3S$ (vitamin B₇, biotin)
C (carbon): 10
H (hydrogen): 16
N (nitrogen): 2
O (oxygen): 3
S (sulfur): 1
Total atoms per formula unit: 10 + 16 + 2 + 3 + 1 = 32
