Question

Question #7504a

Answer 1

Here's what I got.

Explanation:

You're actually dealing with a coordination compound called hexamminechromium(III) nitrate, which consists of the hexaamminechromium(III) complex ion, `"Cr"("NH"_3)_6^(3+)`, and the nitrate anion, `"NO"_3^(-)`.

More specifically, the coordination compound consists of one hexamminechromium(III) complex ion and three nitrate anions.

So, how many elements are a part of this compound? To figure that out, break up the complex ion and the nitrate anion into their respective constituent elements.

Notice that `6` subscript that follows the ammonia ligands. This means that the complex ion contains six ammonia molecules, `"NH"_3`, so make sure that you keep track of all these atoms.

You can thus say that `"Cr"("NH"_3)_6^(3+)` contains

• one chromium atom, `"Cr"`
• six nitrogen atoms, `"N"`
• eighteen hydrogen atoms, `"H"`

Now focus on the nitrate anion. Notice that it has a `3` subscript, so keep that in mind when listing the number of atoms it contains.

You can say that three nitrate anions, `3 xx"NO"_3^(-)`, will contain

• three nitrogen atoms, `"N"`
• nine oxygen atoms, `"O"`

So, this coordination compound contains four distinct elements

• chromium
• hydrogen
• nitrogen
• oxygen

Add up all the atoms we've listed above to get the total number of atoms per element

• chromium: `1 ->` from the complex ion
• hydrogen: `18 ->` all from the complex ion
• nitrogen: `9 ->` `6` from the complex ion and `3` from the three nitrate anions
• oxygen: `9 ->` all from the nitrate anions

The total number of atoms present in the compound will be

`"no. of atoms" = 1 + 18 + 9 + 9 = 37`