​RECAP QUESTIONS

Representation of the elements​

• Elements are symbolized by 1 or 2 letters

• Example C, O, F, Mg, Na

​Symbols of elements

• • Protons and Neutrons contribute to the mass of the atom

  • Electrons DO NOT contribute to the mass of the atom BECAUSE they are TOO SMALL

  • PROTONS + NEUTRONS = Mass Number

Mass Number (A)

​Atomic Number (Z)

• This is the number of protons in the nucleus of an atom​

​Neutral Atoms

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Neutral atoms have to have the SAME number of protons and electrons because the (+) and (-) charges will cancel out.

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​Therefore the number of electrons is equal to the atomic number (number of protons)

Calculating the Number of Neutrons​

​Number of Neutrons

• ​To find the number of neutrons in an atom subtract the atomic number from the mass number

• ​Number of neutrons = Mass number (A) - Atomic number (Z)

​THE END

​Ill SEE YOU NEXT YEAR ❤

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