Exploring Atoms
Name:
1. How many atoms are there in a single grain of sand?
2. Name the 3 subatomic particles that make up every atom.
1. _______________ 2) _______________ 3) ________________
3. What do we call the dense center of every atom?
4. Circle the names of the 2 types of subatomic particle found at the dense center of an
atom:
Protons
/
Neutrons
/
Electrons
5. How much of an atom’s mass is in its nucleus?
6. Some subatomic particles carry a positive charge, some carry a negative charge and
some have no charge. Indicate below which particles carry which charge.
Particle Type Particle Charge
Proton
Electron
Neutron
7.
Every atom is electrically neutral, which means the number of negatively charged
particles is equal to the number of positively charged particles in that atom. Knowing
this, answer the questions below:
a.
An atom with 5 protons must also have __________ electrons.
b.
An atom with 12 electrons must have ___________ protons.
c.
An atom with 20 protons must also have 20 ___________________.
d.
An atom always has the same number of ______________ as ______________.
8. Which of these is true about the Atomic Number? Circle true or false.
a.
The atomic number gives an atom its unique identity.
T / F
b.
The atomic number is equal to the number of protons in an atom.
T / F
c.
The atomic number also tells us how many electrons are in an atom.
T / F
d.
The atomic number is equal to the atomic weight of the atom.
T / F
9. Label the following diagram of a Helium atom with the names of the subatomic
particles:
10. The Atomic Number gives an atom its unique identity.

An atom with 79 protons is always called Gold.

An atom with 29 protons is always called Copper.
Use information from each diagram and the Periodic Table to determine what the
name of the atom is.
a)
b)
c)
Protons _________
Protons _________
Atomic Number _________
Atomic Number _________
Protons _________
Name of atom ___________
Name of atom ___________
Atomic Number _________
Name of atom ___________