Question

counting atoms practice
identify the number of atoms for each element in the following compounds.

1. mg(oh)₂ mg = o = h =
2. caco₃ ca = c = o =
3. ba₃(po₄)₂ ba = p = o =
4. fe(cn)₃ fe = c = n =
5. ccl₄ c = cl =
6. na₂so₄ na = s = o =
7. srf₂ sr = f = o =
8. nh₄no₃ n = h = o =
9. ch₃cooh c = h = o =
10. cu(no₃)₂ cu = n =

Explanation:

Step1: Analyze $Mg(OH)_2$

$Mg$ has 1 atom, $O$ has $1\times2 = 2$ atoms, $H$ has $1\times2 = 2$ atoms.

Step2: Analyze $CaCO_3$

$Ca$ has 1 atom, $C$ has 1 atom, $O$ has 3 atoms.

Step3: Analyze $Ba_3(PO_4)_2$

$Ba$ has 3 atoms, $P$ has $1\times2=2$ atoms, $O$ has $4\times2 = 8$ atoms.

Step4: Analyze $Fe(CN)_3$

$Fe$ has 1 atom, $C$ has $1\times3 = 3$ atoms, $N$ has $1\times3 = 3$ atoms.

Step5: Analyze $CCl_4$

$C$ has 1 atom, $Cl$ has 4 atoms.

Step6: Analyze $Na_2SO_4$

$Na$ has 2 atoms, $S$ has 1 atom, $O$ has 4 atoms.

Step7: Analyze $SrF_2$

$Sr$ has 1 atom, $F$ has 2 atoms, $O$ has 0 atoms.

Step8: Analyze $NH_4NO_3$

$N$ has $1 + 1=2$ atoms, $H$ has $4$ atoms, $O$ has 3 atoms.

Step9: Analyze $CH_3COOH$

$C$ has $1+1 = 2$ atoms, $H$ has $3 + 1=4$ atoms, $O$ has 2 atoms.

Step10: Analyze $Cu(NO_3)_2$

$Cu$ has 1 atom, $N$ has $1\times2 = 2$ atoms, $O$ has $3\times2 = 6$ atoms.

Answer:

Compound	$Mg$	$O$	$H$	$Ca$	$C$	$Ba$	$P$	$Fe$	$N$	$Cl$	$Na$	$S$	$Sr$	$F$	$Cu$
$CaCO_3$		3		1	1
$Ba_3(PO_4)_2$		8				3	2
$Fe(CN)_3$					3			1	3
$CCl_4$					1					4
$Na_2SO_4$		4									2	1
$SrF_2$		0											1	2
$NH_4NO_3$		3	4						2
$CH_3COOH$		2	4		2
$Cu(NO_3)_2$		6							2						1