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Counting Atoms and Elements

Total questions: 42

Worksheet time: 28mins

Name
Class
Date
1.

How many atoms of Hydrogen are in H2O

a)

1

b)

2

c)

3

d)

more than 3

2.

How many different elements are present in H2COCH2

a)

5

b)

4

c)

3

d)

2

3.

Calculate the number of Oxygen atoms in Al(OH)3

a)

1

b)

2

c)

3

d)

4

4.

How many Magnesium atoms are in 10MgCl2?

a)

10

b)

5

c)

20

5.

How many atoms are there TOTAL in H2SO4 ?

a)

6

b)

5

c)

7

d)

3

6.

How many Sodium atoms are in 6NaCl?

a)

1

b)

12

c)

6

7.

How many total POTASSIUM atoms are in this formula?

a)

8

b)

2

c)

4

d)

12

8.

What determines the reactivity of an element?

a)

protons

b)

neutrons

c)

electrons

d)

valence electrons

9.
Which is the correct formula for:
 three hydrogen (H)
one sulfur (S)
four oxygen (O)
a)
H3SO4
b)
HSO4
c)
H4S3O
d)
H2O
10.

What does the subscript in a chemical formula tell you?

a)

How many molecules are present

b)

How many atoms are present

c)

How many elements are present

d)

How many neutrons are present

11.

How many elements are in this chemical formula? NaHCO3NaHCO_3  

a)

1

b)

2

c)

3

d)

4

12.

How many atoms/ions are in one formula unit of Zn(C2H3O2)2 ?

(a)  

13.

How many atoms of Hydrogen are in this compound?

a)

1

b)

2

c)

3

d)

4

14.

NaCl is the chemical formula for salt. Is NaCl considered a compound or an element?

a)

element

b)

compound

c)

both

d)

neither

15.

We breathe oxygen. Its chemical formula is O2. Is this formula an element or a compound?

a)

element

b)

compound

c)

neither

d)

both

16.
Which of the following is a compound?
a)
Co
b)
O2
c)
C
d)
CO2
17.
The red numbers in the image below represent ________
a)
subscripts
b)
coefficients
c)
I don't know, and don't want to try
d)
None of the answers are correct
18.
The blue numbers in the image below represent ________
a)
I don't know, and don't want to try
b)
coefficients
c)
subscripts
d)
none of the answers are correct
19.
How many Valence Electrons does Argon have?
a)
2
b)
3
c)
8
d)
18
20.
Which equation obeys the law of conservation of mass?
a)
H2 + O2 ------>  H20
b)
C + 2H2 ---->  CH4
c)
2Fe2O3  ------> 2O2 + 4Fe
21.

How man atoms of carbon are there?

a)

1

b)

2

c)

3

d)

4

22.

How many atoms of Iron are in this compound?

a)

1

b)

2

c)

3

d)

4

23.

How many atoms of hydrogen are in

C6H12O6

a)

6

b)

12

c)

18

d)

2

24.

A substance made up of atoms of two or more different elements joined by chemical bonds

a)

Molecule

b)

compound

c)

polar covalent bond

d)

nonpolar covalent bond

25.

How many different elements are present in H2COCH2

a)

5

b)

4

c)

3

d)

2

26.

Calculate the number of Oxygen atoms in Al(OH)3

a)

1

b)

2

c)

3

d)

4

27.

How many total POTASSIUM atoms are in this formula?

a)

8

b)

2

c)

4

d)

12

28.

How many elements are in this chemical formula? NaHCO3NaHCO_3  

a)

1

b)

2

c)

3

d)

4

29.

Coefficients in chemical formulas...

a)

Multiply just the first atom

b)

Add to the subscripts at the end of the molecule

c)

Multiply elements without subscripts

d)

Multiply EVERYTHING!

30.

C3H5(NO3)3

a)

C = 3, H = 5, N = 3, O = 9

b)

C = 3, H = 5, N = 1, O = 9

c)

C = 9, H = 15, N = 3, O = 9

d)

C = 9, H = 15, N = 1, O = 3

31.

What is the symbol for Potassium

a)

P

b)

Po

c)

K

d)

Pt

32.

Which element has the symbol Cl

a)

Carbon

b)

Chlorine

c)

Cadium

d)

Copper

33.

What is the symbol for Sodium

a)

S

b)

Au

c)

So

d)

Na

34.

What is the symbol for Magnesium

a)

Mn

b)

Mc

c)

Mg

d)

Md

35.

What is the symbol for Iron?

a)

Ir

b)

In

c)

Fe

d)

FE

36.
the central region of an atom where its neutrons and protons are is its 
a)
nucleus 
b)
electron cloud
c)
core 
d)
center 
37.

The positive parts of an atom are 

a)
electrons 
b)
positrons 
c)
neutrons 
d)
protons 
38.
Particles in an atom that are neutral and have no charge are 
a)
negatrons 
b)
electrons 
c)
neutrons 
d)
protons 
39.
electrons have this type of charge?
a)
negative
b)
positive
c)
neutral
40.
These particles orbit around the nucleus of an atom.  What are they called?
a)
electrons
b)
protons
c)
neutrons
d)
photons
41.
How does the size of a proton compare to the size of a neutron?
a)
larger
b)
smaller
c)
equal
42.
An atom with atomic number 6 would have how many protons 
a)
6
b)
12
c)
3
d)
cannot be determined 

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