Use the Bohr-Rutherford simulator to connect atomic number, protons, electrons, neutrons, ions, isotopes, and periodic-table patterns.
Lesson Focus
Anchor question: how can every sample of carbon be carbon, but not every carbon atom be exactly the same? Today you will build atoms, change their particles, and use those patterns to explain what makes an element an element.
Section 1Build Atoms in the Sim~20 min
Reference
Protons are positive particles in the nucleus. The number of protons identifies the element.
Neutrons are neutral particles in the nucleus. Changing neutrons can make an isotope.
Electrons are negative particles around the nucleus. Changing electrons can make an ion.
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Open the Bohr-Rutherford Simulator
Build atoms by changing protons, neutrons, and electrons. Watch the element name, mass, charge, shells, and Lewis dot diagram update as you work.
Change only the number of neutrons. Notice what changes and what stays the same.
3
Return to neutral carbon, then change only the number of electrons. Notice what happens to charge.
4
Try oxygen, sodium, and chlorine. Use the periodic table clues in the sim.
Build This Atom or Ion
Element Name
Mass Number
Charge
What Changed?
6p, 6n, 6e
6p, 8n, 6e
6p, 6n, 7e
8p, 8n, 10e
1p, 0n, 1e
2p, 2n, 2e
3p, 4n, 2e
4p, 5n, 2e
9p, 10n, 10e
10p, 10n, 10e
12p, 12n, 10e
20p, 20n, 18e
Section 2Find the Rules~25 min
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Pattern hunt
Use your table above and the sim. Your job is not just to fill in facts. Your job is to write rules that would help another student build atoms correctly.
Rule 1
Which particle decides the identity of the element?
Rule 2
Which particle changes the mass number without changing the element?
Rule 3
What happens when an atom has more electrons than protons?
Rule 4
What happens when an atom has fewer electrons than protons?
Periodic Table Pattern
Build the alkali metals lithium, sodium, and potassium. What do you notice about their electrons?
Hint: look closely at the outermost electrons. Use this to explain why elements in the same group often behave in similar ways.
Section 3Use the Model~20 min
Before You Classify
An atom is neutral when it has the same number of protons and electrons.
An ion is charged because it has gained or lost electrons.
An isotope is a version of the same element with a different number of neutrons. The element stays the same because the number of protons stays the same.
Situation
Atom, Ion, or Isotope?
Explain Your Choice
A chlorine particle has 17 protons, 18 neutrons, and 18 electrons.
A carbon particle has 6 protons, 8 neutrons, and 6 electrons.
A sodium particle has 11 protons, 12 neutrons, and 10 electrons.
!
Final Task
Karen says, "If you change any particle in an atom, you always make a different element." Correct her using protons, neutrons, and electrons.
Karen Prompt
Write a short correction. Include at least one example from the simulation.
Exit Ticket
Answer the anchor question: how can every sample of carbon be carbon, but not every carbon atom be exactly the same?
Finished?
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