20 How do you determine the number of barium atoms in the formula below?
4Ba(OH)2
F
# of Ba atoms = coefficient 4 + subscript 1 = 5
G
# of Ba atoms = coefficient 4 X subscript 1 = 4
H
# of Ba atoms = subscript 4 X coefficient 2 = 6
# of Ba atoms coefficient 1 + subscript 1 = 2
J

G is correct option:

# of Ba atoms = coefficient 4 × subscript 1= 4

Explanation:

Formula:

4Ba(OH)₂

G is correct option:

# of Ba atoms = coefficient 4 × subscript 1= 4

Because there are only 4 atoms of Ba in given formula.

Ba(OH)₂ contain one atom of Ba while in question there are 4 moles of Ba(OH)₂ present thus total 4×1 = 4 atoms of Ba present.

Other options are incorrect. Because,

F:

# of Ba atoms = coefficient 4 + subscript 1 = 5

This shows given formula contain 5 Ba atoms. So it is incorrect.

H:

# of Ba atoms = subscript 4 ×  coefficient 2 = 6

This shows that subscript is 4 which is incorrect because coefficient is 4 and subscript is 1.  

j:

# of Ba atoms = subscript 1  + coefficient 1 = 2

This option shows that subscript is one which is correct but coefficient is incorrect. The coefficient of Ba is 4 and coefficient is always multiply with subscript not added. So this option is also incorrect.