ATOM
Nearly 2500 years ago, the ancient Greeks proposed that all matter is made of
extremely small particles called atoms. Until recently, no one had ever seen an
atom. The ancient Greeks based their ideas about atoms on reasoning and
logic. Not until the 1700s did scientist begin to collect daya that led to the
development of atomic theory. The atomic theory states that all matter is made
of atoms. An atom is defined as the smallest unit of an element that retains all
the properties of that element.
In 1808 , Jonh Dalton, an English schoolteacher studied the various
experimental data that had been collected about atoms. He then looked at what
the ancient Greeks had said about atoms. Piecing together all the information,
Dalton developed the first modern atomic theory. Dalton´s theory had one major
advantage over all the ealier ideas about atoms.
Dalton´s theory colud be tested by experiments. Some of what Dalton proposed
was found to be correct.
Other parts of Dalton´s theory were eventually replaced as new informations
about atoms was collected.
One of Dalton´s proposals that was eventually discarded was his idea that an
atom could not be divided into smaller particles. Today, scientist know that an
atom can be divided into numerous smaller particles. Three major subatomic
particles are now known. These three particles are the proton, the neutron and
the electron.
A proton is a subatomic particle that has a positive charge usually written as
+1. A neutron is a subatomic particle that is neutral. This neutral charge is
usually written as 0. The protons and neutrons are located in the central region
of an atom. This region is called the nucleus. A nucleus of an atom is the
dense, central portion of an atom where all its protons and neutrons are located.
An electron is a subatomic particle that has a negative charge, usually written
as -1. All atoms are electrally neutral because every atom has an equal number
of protons and electrons. Unlike the protons and neutrons, electrons are located
outside the nucleus. The current model of an atom shows electrons orbiting the
nucleus, where the protons and neutrons are located.
The number of protons an atom has is known as its atomic number. The total
number of protons and neutrons of the nucleus is known as an atom´s mass
number.
NAME: ________________________________
___________
DATE:
ATOM
Name the three subatomic particles.
Atomic structure: Not to scale
1. Name the parts that make up a nucleus. _____________ ____________
.
2. A proton is _________________________ than an electron.
Larger, smaller
3. An electron is _____________________ than a neutron.
Larger, smaller
4. A proton has ______________________ charge.
Positive, negative, no
5. An electron has ________________________ charge.
Positive, negative, no
6. A neutron has _________________________ charge.
Positive, negative, no
NAME: ________________________________
___________
DATE:
ATOM
The list on the bottom contains words that you have used in this Lesson.
Find and circle each word where it appears in the box. The spellings may go
in any direction: up, down, left, right or diagonally.
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PROTONS
NEUTRONS
ELECTRONS
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NUCLEUS
ATOMIC
ELEMENT
NAME___________________________ DATE____________
GROUP______
EXPERIMENT: ATOM MODEL
To understand how atoms are arranged, you can build this model of an atom
and its electron shells. Of course, atoms are not really like this inside; it is
simply a convenient way of thinking about them.
MATERIAL:

2 BLUE PAPERS (FIRST AND THIRD SHELL)

1 ORANGE PAPER (SECOND SHELL)

YELLOW NUCLEUS

RED PAPER (ELECTRONS)

WHITE LARGE PAPER

SCISSORS

GLUE
PROCEDURE:
1. Cut the three big circles with scissors (blue and orange paper). These
form the three shells.
2. Stick the circles onto the white paper on the left, starting with the largest.
It is simplest to stick them on top of each other.
3. Cut the small yellow circle. This forms the nucleus.
4. Cut really small circles with scissors (red paper). These form electrons.
5. Stick electrons onto the edge of each shell.
Remember: Atoms have at most seven electrons shells, and there is a limit
to the number of electrons that can fit into each. In the first shell, there is
only space for 2 electrons; in the second, 8 electrons; in the third 18
electrons. After that it becomes very complex.
6. Indicate what everything is, on the right of the white paper.
NAME___________________________________________DATE_________
EXPERIMENT QUESTION: Can two kinds of matter to take up
the same space at the same time?
MATERIAL:

3 plastic cups with water

A ruler

A beaker with orange juice

A marker

Rocks

Data sheet

One straw
PROCEDURE:
ADDING A SOLID TO A LIQUID (Plastic cup 1)
1. Use your marker to draw a line on the cub 1 which shows how high the water is
in the cup. Do not draw a line which goes up and down. Draw a line straight
across the cup.
2. Use a ruler to measure the line and record the measurement on the data sheet.
3. Put the rocks into the cup 1.
4. Put a new mark on the cup to show how high the water is in the cup now.
5. Measure the mark and record it on your data sheet.
6. Subtract the first mark from the second mark to see how much space the rocks
took up and record it on your data sheet.
ADDING A GAS TO A LIQUID (Plastic cup 2)
1. Use your marker to draw a line on the cub 2 which shows how high the water is
in the cup. Do not draw a line which goes up and down. Draw a line straight
across the cup.
2. Use a ruler to measure the line and record the measurement on the data sheet.
3. Put your straw in the water and blow some gas into it while another team
member puts a mark on the cup to show how high the water in the cup went
when you blew gas into it.
4. Measure the mark and record it on your data sheet.
5. Subtract the first mark from the second mark to see how much space the gas
took up and record it on your data sheet.
ADDING A LIQUID TO A LIQUID (Plastic cup 3)
1. Use your marker to draw a line on the cub 3 which shows how high the water is
in the cup. Do not draw a line which goes up and down. Draw a line straight
across the cup. Record the measurement on the data sheet.
2. Use a ruler to measure the line and record the measurement on the data sheet.
3. Add the orange juice into the cub 3.
4. Put a new mark on the cup to show how high the water in the cup went when
you put another liquid into it.
5. Measure the mark and record it on your data sheet.
6. Subtract the first mark from the second mark to see how much space the other
liquid took up and record it on your data sheet.
RESULTS: What did you observe when you
add the rocks to the water?
_____________________________________________________________________
___
_____________________________________________________________________
_____________________________________________________________________
______
add gas to the water?
_____________________________________________________________________
___
_____________________________________________________________________
_____________________________________________________________________
______
add orange juice to the water?
_____________________________________________________________________
___
_____________________________________________________________________
_____________________________________________________________________
______
CONCLUSION: (What is the answer to the experiment question?)
_____________________________________________________________________
_____________________________________________________________________
_____________________________________________________________________
_____________________________________________________________________
_____________________________________________________________________
_______________
NAME___________________________________________DATE_________
A CLOSER LOOK AT GASES
CHARACTERISTICS OF GASES:
PROCEDURE
1. Follow the procedure steps on your experiment form. Be certain to check
each of the steps as you do them.
2. Draw on the observation form as events occur in the experiment.
3. Discuss the conclusion. Remember that you are trying to answer the
experiment question.
EXPERIMENT FORM
EXPERIMENT QUESTION: Can two liquids form a gas?
Hypothesis: What do you think will happen?
_____________________________
__________________________________________________________________
1. Add all seltzer you have in the bottle into the balloon.
2. Stretch the balloon top over the top of the vinegar bottle, being careful to let
the “bag” part of the balloon hang over the side of the vinegar bottle.
3. Pick up the “bag” part of the balloon and let the seltzer go out of the balloon
into the vinegar bottle.
4. Shake the bottle.
5. Observe with your eyes, ears and hands to see what happens.
CONCLUSION: