Subatomic Particles Atomic Number and Atomic Mass Subatomic

Subatomic Particles, Atomic Number and Atomic Mass

Subatomic particles Name Symbol Relative Charge mass Actual mass (g) Electron e- -1 1/1840 9. 11 x 10 -28 Proton p+ +1 1 1. 67 x 10 -24 Neutron no 0 1 1. 67 x 10 -24 http: //www. unit 5. org/christjs/site%20 map. htm

Structure of the Atom There are two regions: 1. The Nucleus: • With protons and neutrons • Positive charge • Almost all the mass 2. Electron cloud • Most of the volume of an atom • The region where the electron can be found http: //www. unit 5. org/christjs/site%20 map. htm

http: //www. andrew. cmu. edu/user/jgrao/Manchester%20 United/giant%20 stadium. jpg If the atom was the size of a stadium, the nucleus would be the size of: a marble. http: //www. akronmarbles. com/marble-frag-2. jpg

Symbols Contain the symbol of the element, the mass number and the atomic number # protons + # neutrons mass number # protons Mass number Atomic number X http: //www. unit 5. org/christjs/site%20 map. htm

• The mass number = # p + # n • The atomic number = #p • In a neutral atom the #e = # p

http: //chemistry. beloit. edu/Stars/EMSpectrum/fluorine. gif Symbols • Find the – number of protons = – number of neutrons = – number of electrons = – Atomic number = – Mass number = 19 9 F http: //www. unit 5. org/christjs/site%20 map. htm

http: //chemistry. beloit. edu/Stars/EMSpectrum/fluorine. gif Symbols • Find the – number of protons = 9 + – number of neutrons = 10 – number of electrons = 9 – Atomic number = 9 – Mass number = 19 19 9 F http: //www. unit 5. org/christjs/site%20 map. htm

Symbols Find the – number of protons = – number of neutrons = – number of electrons = – Atomic number = – Mass number = 80 35 Br http: //www. unit 5. org/christjs/site%20 map. htm

Symbols Find the – number of protons = 35 – number of neutrons = 45 – number of electrons = 35 – Atomic number = 35 – Mass number = 80 80 35 Br http: //www. unit 5. org/christjs/site%20 map. htm

Ions • In an ion – a charged particle the charge can be either + or -. The # of protons and neutrons remains the same. It is only the electrons that are gained or lost to create the charge • Mass number = #p + #n • For an ion the #e ≠ #p • adding an electron produces a negative ion • Subtracting an electron produces a + ion

Symbols Find the – number of protons = – number of neutrons = – number of electrons = – Atomic number = – Mass number = 23 11 Na 1+ Sodium ion http: //www. unit 5. org/christjs/site%20 map. htm

Symbols Find the – number of protons = 11 – number of neutrons = 12 – number of electrons = 10 – Atomic number = 11 – Mass number = 23 23 11 Na 1+ Sodium ion http: //www. unit 5. org/christjs/site%20 map. htm

http: //www. webelements. com/webelements/media/nearingzero/Na. gif

Symbols If a neutral atom of an element has 78 electrons and 117 neutrons what is the – Number of protons – Atomic number – Mass number – Complete symbol http: //www. findajeweler. com/fashion_trends/2004/July/images/pt_sample. gif http: //www. radiochemistry. org/periodictable/elements/images/78. gif

Symbols If a neutral atom of an element has 78 electrons and 117 neutrons what is the – Number of protons = 78 – Atomic number = 78 – Mass number = 78 + 117 = 195 – Complete symbol = Pt http: //www. findajeweler. com/fashion_trends/2004/July/images/pt_sample. gif http: //www. radiochemistry. org/periodictable/elements/images/78. gif