How many protons electrons and neutrons 1

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1. How many protons, electrons,
and neutronsare in an atom?
http://physicsed.buffalostate.edu/Wiley/CJ6e/img30/PTE.gif

2. Step 1
Use your periodic
table to find an
element
http://education.jlab.org/qa/pen_number.html

3. Step 2
The number of Protons (+ charge)
The atomic number = # protons
Kr has 36 protons
http://education.jlab.org/qa/pen_number.html

4. Step 3
The number of Electrons (-charge)
Remember atoms have no overall charge.
Atoms must have an equal # of protons and
electrons
#protons=#electrons
Kr has 36 electrons

5. Step 4
The number of Neutrons (no charge)
Mass #(atomic weight rounded to nearest whole #)
Neutrons =Mass # -Protons
Neutrons=84–36
Neutrons =48

6. Summary
Number of Protons= Atomic #
Number of Electrons= Protons
Number of Neutrons= Mass #-Protons

7. Problems
1.Find the protons (p+), electrons (e-),
neutrons (n) of Oxygen
2.Find the p+, e-, n of Xenon (Xe)
3.Find the p+, e-, n of Zirconium (Zr)

8. Oxygen (O)
p+, e-, n
Number of Protons= Atomic #
Number of Electrons= Protons
Number of Neutrons= Mass #-Protons
Protons = 8
Electrons = 8
Neutrons = 16-8 = 8

9. Xenon (Xe)
p+, e-, n
Number of Protons= Atomic #
Number of Electrons= Protons
Number of Neutrons= Mass #-Protons
Protons = 54
Electrons = 54
Neutrons = 131-54 = 77

10. Zirconium (Zr)
p+, e-, n
Number of Protons= Atomic #
Number of Electrons= Protons
Number of Neutrons= Mass #-Protons
Protons = 40
Electrons = 40
Neutrons = 91-40 = 51