Counting Atoms

How many Hydrogen atoms are in 4 H₂O? ​ (a)   How many oxygen atoms? ​ (b)  

• 8
• 4
• 1
• 2
• 3
• 5
• 6
• 7
• 9

3(NH₄)₂CrO₄

Number of N: ​ ​ (a)  

Number of H: ​ (b)  

Number of Cr: ​ (c)  

Number of O: ​ (d)  

• 6
• 24
• 3
• 12
• 4
• 8
• 1
• 2
• 9

2 CH₂CO₃OH

Number of C: ​ (a)  

Number of H: ​ (b)  

Number of O: ​ (c)  

• 4
• 6
• 8
• 2
• 3
• 1
• 5
• 7
• 9
• 10

Match the element to the number of atoms it has.

2 Al(C₂H₃O₄)₂

• 12

• hydrogen

• 8

• carbon

• 2

• aluminum

• 16

• oxygen

What does the subscript in a chemical formula tell you?

• How many molecules are present

• How many atoms of each element there are.

• How many elements are present

• How many neutrons are present

• Iron, Oxygen

• Francium, Europium, Oxygen

• Ferrium, Oxygen

• Berylium, Oxygen

• Silver

• Gold

• Nitrogen

• Oxygen

______ are little numbers found on the lower right-hand side AFTER an element symbol.

• Coefficients

• Exponents

• Multipliers

• Subscripts

Coefficients in chemical formulas...

• are found at the beginning of a formula and multiply just the first atom

• are found at the end of a formula and multiply EVERYTHING!

• are found at the end of a formula and multiply only elements inside the parentheses.

• are the BIG numbers written in front of a chemical formula and tells you how many molecules of that substance there are.

3 H₂SO₄

There are ​ (a)   hydrogens, ​ (b)   sulfurs, and ​ (c)   oxygens

• 6
• 3
• 12
• 2
• 4
• 1