School Rocks!

 

   

 

Exploring positive and negative charges - atoms lesson 2

By Kim Fleming

Standards Match:

Standard 1: Students will understand the structure of matter.

Objectives:

bulletThe goal is to answer to the question "What is an atom made of?”
bulletAn atom, the smallest unit of an element, is made up of 3 main pieces: electrons, protons, and neutrons.
bulletEach element has a unique combination of protons and electrons in its atoms
bulletProtons are particles with a positive (plus) charge.  Electrons are particles with a negative (minus) charge.
bulletBe able to describe or draw a picture of: atoms, protons, electrons, and atomic number
bulletStudent will understand why each element has a specific place in the periodic table

Time:40 minutes

Materials:

bulletRope
bulletNumber Line
bulletScience Journals

Lesson

  1. Hands on physical Activity

·        Two people of equal strength pulling on two ends of a rope

·        Two people of equal strength pushing their backs against each other

·        One stronger person pushing

·        One stronger person pulling

  1. Let’s put these scenarios on a number line (just like in addition, plus takes us to the right and minus or negative takes us left – a quick review with easy numbers might be a good idea – like 6-4 is really plus six goes 6 right from the zero and -4 is go left from where the 6 leaves you)

 

·        (+1, -1) (+3, -3) (-1, +1) (-3, +3) ( +6, -2) (-6, +2)

  1. 3 people on each end of the rope ( won’t go anywhere if they are the same strength)
  2. Inside atoms, the same thing is going on.
bulletThere are 3 main parts – subatomic particles (like a submarine is inside the water – subatomic is inside the atom)

1.      Protons – Pro + (like a pro football player – pushing forward) RED IN PIC

2.      Electrons – negative – (think of all the negative advertising in elections) BLACK IN PIC

3.      Neutrons – neutral – (I’m not going one way or the other – I’m staying out of your fight) NOT IN THE PICTURES BELOW

·        If we take an atom of any element,  for it to be neutral it must have EXACTLY the same number of protons (positive force) and electrons (negative force)

·        Each neutral element has a specific and unique (no other one like it) number of protons and electrons

o       Question: An atom of the element helium in outer space has (the same, a different)________ combination of electrons and protons as that of an atom of helium on earth?

o       Question:   Since each element has a know unique number of protons and electrons in its atoms, would it be possible to identify an element if you know the number of protons and electrons in its atoms?_______________

o       Question: A boron atom contains five protons.  We assume the atom to be neutral.  How many electrons must it have?______________

o       If an atom contains eight electrons.  How many protons does it contain?_____

·        The periodic table is a very useful table describing the atoms of every know element in the universe. This is what the periodic table looks like.

o       Each box is a shorthand notation used to represent a neutral atom of an element. 

o       The symbol “C represents a neutral atom of the element carbon. 

o       The symbol “He” represents a neutral atom of the element helium

The number of protons in an atom is listed above each symbol. (Ignore the number underneath thee symbol for now.)

                                       

·       

o       Since the number of electrons in a neutral atom is equal to the number of protons, do you think we can identify an element if we know just the number of protons in it’s atoms? ___________

o       What  is the ATOMIC NUMBER for the following elements? What is the element?

Text Box: Electrons in Black       Protons in Red

 

  1. Questions:
bulletThe element zinc (Zn) has an atomic number of 30.  How many protons does an atom of zinc contain?__________________
bulletA neutral atom of zinc contains how many electrons?__________________
bulletUsing the periodic table, determine the number of electrons in a neutral atom of copper (Cu).__________________
  1. What did we learn:
    bulletWhat is the smallest piece of an element?
    bulletWhat are the three subatomic particles that make up an atom?
    bulletIs a proton positively or negatively charged?
    bulletIs an electron positively or negatively charged?
    bulletHow many protons does an atom contain? How can you tell?
    bulletWhy is H the first element in the periodic table

Journaling (review/summary)

bulletDraw a picture that will remind you about what you learned today
bulletWrite in words what you learned today.  How would you explain it to a 3rd grader?
bulletAlways questions – what comes next? – what do you wonder about now?

Looking Ahead

We are going to be working with the elements in the periodic table over and over again, so we will need to learn the shorthand symbols to make the next steps easier.  I’m going to show you some tricks that helped me learn them, and you will be working in groups to develop your own way of remembering them

Personal Teaching Reflection: Look for specific things that might improve the lesson.  See if students seemed engaged.  Look for personal interests to tie problems to real life. 

bulletWhat worked?
bulletWhat didn’t work?
bulletWhat would improve this lesson?