Build an Atom Activity
Name: _______________________________________ Date: _________________ Hour: ________________
Knowledge Probe: Read pages 318 – 324 in the blue Physical Science Textbook and answer the
following questions.
1. Which of the following statements is true?
a. A penny has about 20,000 atoms.
b. A penny has more atoms than Earth has people.
c. Aluminum is made up of large-sized atoms.
d. Aluminum atoms have a diameter of about 3 cm.
Matching – Match the correct description with the correct term.
Electron
Atomic mass unit (amu)
Nucleus
Proton
Ion
Neutron
2. _______________ is the particle of the nucleus that has no electrical charge.
3. _______________ is the particle found in the nucleus that is positively charged.
4. _______________ is a particle with an unequal number of protons and electrons.
5. _______________ are negatively charged particle found outside the nucleus.
6. _______________ contains most of the mass of an atom.
7. _______________ is the SI unit used for the masses of atomic particles.
How do atoms of different elements differ?
8. Neutrons in the atom’s ____________________ keep two or more protons from moving apart.
9. An atom does not have to have equal numbers of ____________________ and ____________________.
10. The number of protons in the nucleus of an atom is the ___________________.
11. _____ Isotopes always have
a. The same number of protons.
b. The same number of neutrons.
c. A different atomic number.
d. The same mass.
12. Which of the following is NOT true about unstable atoms?
a. They are radioactive.
b. They have a nucleus that always remains the same.
c. They give off energy as they fall apart.
d. They give off smaller particles as they fall apart.
13. Most elements contain a mixture of two or more ____________________.
14. The weighted average of the masses of all the naturally occurring isotopes of an element is the
____________________.
Observations: Now you will observe some models atoms to discover how they are identified and
classified.
Part 1: Make some observations about your atoms.
1. Describe their composition (what are they made of)?
Part 2: How do you know which element an atom is?
What is in your atom?
1
Element Name
# of protons: __________
# of neutrons: _________
# of electrons: ________
2
# of protons: __________
# of neutrons: _________
# of electrons: ________
3
# of protons: __________
# of neutrons: _________
# of electrons: ________
4
# of protons: __________
# of neutrons: _________
# of electrons: ________
5
# of protons: __________
# of neutrons: _________
# of electrons: ________
2. What is a good rule for determining which element an atom is?
3. Here is an element from the periodic table. Circle the number that makes nitrogen
different from other elements. Does that number represent the number of protons,
neutrons or electrons?
Part 3: How can you determine the mass of an atom?
What is in your atom?
1
Element Name
Mass of Element
# of protons: __________
# of neutrons: _________
# of electrons: ________
2
# of protons: __________
# of neutrons: _________
# of electrons: ________
3
# of protons: __________
# of neutrons: _________
# of electrons: ________
4
# of protons: __________
# of neutrons: _________
# of electrons: ________
5
# of protons: __________
# of neutrons: _________
# of electrons: ________
4. What is a good rule for determining the mass of an atom?
5. What number indicates the mass of nitrogen? Why isn’t it a whole number? (See
number 14 in the knowledge probe.)
Part 4: Isotopes: Two of the same element that has different masses.
6. Identify the isotopes you have labelled in part 3 by writing the name of the element, followed by a dash
and the mass of that isotope. (Fluorine – 19 and Fluorine - 18)
Part 5: Ions: An atom that is charged either positive or negative.
Protons have a positive charge, electrons have a negative charge and neutrons do not have a charge. To
determine the charge of an atom one must consider the number of protons and the number of electrons. If an
atom has the same number of protons and electrons it is electrically neutral (because all of the positive charge is
cancelled out by the negative charges). If there are more protons than electrons then it is positively charged. If
there are more electrons than protons then it is negatively charged. Try to determine the charges of the
following atoms.
What is in your atom?
1
# of protons: __________
# of neutrons: _________
# of electrons: ________
2
# of protons: __________
# of neutrons: _________
# of electrons: ________
3
# of protons: __________
# of neutrons: _________
# of electrons: ________
4
# of protons: __________
# of neutrons: _________
# of electrons: ________
5
# of protons: __________
# of neutrons: _________
# of electrons: ________
Element Name
Mass of Element
What is the charge?
Wrap-Up: Use the periodic table to answer the following questions.
1. Choose an element.
a. Name of element: _______________________
b. How many protons does it have? __________
c. What is its mass? (Round to the nearest whole number) __________
d. How many neutrons does it have? __________
e. How many electrons does an atom of it have? __________
2. Choose another element with fewer than 21 protons.
a. Name of element: _______________________
b. How many protons does it have? __________
c. What is its mass? (Round to the nearest whole number) __________
d. How many neutrons does it have? __________
e. How many electrons does an atom of it have? __________
f.
Draw a picture of atom use different colors to represent the protons, neutrons and electrons.
Draw a key to indicate what each color represents.