Counting Atoms Worksheet - Owasso Public Schools

1 Name: _____ Date: _____ Hour: _____. ** Counting Atoms Practice **. Use your Counting Atoms Notes and Period Table to help you on this assignment. You may use a calculator if you need it. Drawing the arrows is strongly encouraged, but not required. Section A: Identify the coefficients and subscripts in the following formulas. If there is not one, write: none means 1. 1) 3 MgCl2 coefficient: _____. Subscript for Mg: _____. Subscript for Cl: _____. 2) V2O5 coefficient: _____. Subscript for V: _____. Subscript for O: _____. 3) 4K2CO3 coefficient: _____. Subscript for K: _____. Subscript for C: _____.

2 Subscript for O: _____. 4) NaC2H3O2 coefficient: _____. Subscript for Na: _____. Subscript for C: _____. Subscript for H: _____. Subscript for O: _____. Section B: You may draw arrows to help you if you want but it is not required. Write the names of the elements in the order they appear in the formula from left to right. If the element appears more than once, only write it once, then add it's Atoms together. 5) 3Na2SO4 # of molecules: _____ 6) 2 ZnSO4 # of molecules: _____. # of elements: _____ # of elements: _____. Name of element: # of Atoms : Name of element: # of Atoms : _____ _____ _____ _____.

3 _____ _____ _____ _____. _____ _____ _____ _____. Total # of Atoms : _____ Total # of Atoms : _____. The #3 is a _____. The #4 is a _____. (coefficient or subscript) (coefficient or subscript). 7) K2CO3 # of molecules: _____ 8) Ba3(PO4)2 # of molecules: _____. # of elements: _____ # of elements: _____. Name of element: # of Atoms : Name of element: # of Atoms : _____ _____ _____ _____. _____ _____ _____ _____. _____ _____ _____ _____. Total # of Atoms : _____ Total # of Atoms : _____. The #3 is a _____. The #3 is a _____. (coefficient or subscript) (coefficient or subscript). 9) Na2 CrO4 # of molecules: _____ 10) 4Al2(CO3)3 # of molecules: _____.

4 # of elements: _____ # of elements: _____. Name of element: # of Atoms : Name of element: # of Atoms : _____ _____ _____ _____. _____ _____ _____ _____. _____ _____ _____ _____. Total # of Atoms : _____ Total # of Atoms : _____. The #4 is a _____. The assumed 1 is a _____. (coefficient or subscript) (coefficient or subscript). 11) Pb(NO3)2 # of molecules: _____ 12) 4Au(IO3)3 # of molecules: _____. # of elements: _____ # of elements: _____. Name of element: # of Atoms : Name of element: # of Atoms : _____ _____ _____ _____. _____ _____ _____ _____. _____ _____ _____ _____. Total # of Atoms : _____ Total # of Atoms : _____.

5 The #3 is a _____. The #4 is a _____. (coefficient or subscript) (coefficient or subscript). 13) CO2 # of molecules: _____ 14) 3 CaCl2 # of molecules: _____. # of elements: _____ # of elements: _____. Name of element: # of Atoms : Name of element: # of Atoms : _____ _____ _____ _____. _____ _____ _____ _____. Total # of Atoms : _____ Total # of Atoms : _____. The #2 is a _____. The #3 is a _____. (coefficient or subscript) (coefficient or subscript). 15) Cr(NH3)6(NO3)3 # of 16) 5Al(C2H3O2)2 # of molecules: _____ molecules: _____. # of # of elements: _____ elements: _____. Name of element: # of Atoms : Name of element: # of Atoms : _____ _____ _____ _____.

6 _____ _____ _____ _____. _____ _____ _____ _____. _____ _____ _____ _____. Total # of Atoms : _____ Total # of Atoms : _____. The #6 is a _____. The #2 is a _____. (coefficient or subscript) (coefficient or subscript). 17) C4H8 FCOOH # of 18) 2(NH4)3PO4 # of molecules: _____ molecules: _____. # of # of elements: _____ elements: _____. Name of element: # of Atoms : Name of element: # of Atoms : _____ _____ _____ _____. _____ _____ _____ _____. _____ _____ _____ _____. _____ _____ _____ _____. Total # of Atoms : _____ Total # of Atoms : _____. The #4 is a _____. The #2 is a _____. (coefficient or subscript) (coefficient or subscript).

7 Section C: Identify the number of Atoms of each element in the following compounds. Again drawing the arrows is strongly encouraged, but not required. 19) 4K2CO3 K = _____ C = ____ O = ____. 20) K2CO3 K = _____ C = ____ O = ____. 21) 3N4O10 N = _____ O = ____. 22) 8Cl2O Cl = ____ O = ____. 23) Ca(C2H3O2)2 Ca = ____ C = ____ H = ____ O = _____. 24) 12 NaBr Na = ____ Br = ____. 25) 3 NaHCO3 Na = ____ H = ____ C = ____ O = ____. 26) 5Ga2(Cr2O7)3 Ga = ____ Cr = ____ O = ____. 27) 4Fe2O3 Fe = ____ O = _____. 28) 6Ba(MnO4)2 Ba = _____ Mn = _____ O = _____. 29) 5Al2(SiO3)2 Al = ____ Si = _____ O = _____.

8 30) 4Au(IO3)3 Au = ____ I = _____ O = _____. 31) SBr2 S = _____ Br = _____. 32) 4Ca(OH)2 Ca = _____ O = _____ H = _____. 33) 5Mg3(PO4)2 Mg = _____ P = _____ O = _____. 34) 3 ClF Cl = _____ F = _____. ** BONUS ** BONUS ** BONUS ** BONUS ** BONUS ** BONUS **. 1) Hg is the symbol for the element: _____. 2) Write a chemical formula that shows 3 molecules of water: _____. Fill in the boxes for the coefficient and subscripts to make the formula match the number of Atoms . The first one has been done for you as an example. Example: Kr = 2 Cl = 12 2 KrCl 6. 3) K = 6 Zn = 3 O=6 K ZnO. 4) Ba = 5 C = 20 H = 20 O = 30 BaC H O.

9 5) Cu = 4 H=8 S=8 O = 24 Cu(HSO ). 6) N=6 H = 24 Cr = 6 O = 21 (NH ) Cr O.