Subatomic Particles, Atomic Number and Atomic Mass

Subatomic particles Actual e- -1 p+ +1 no mass (g) Relative mass Name Symbol Charge Electron e- -1 1/1840 9.11 x 10-28 Proton p+ +1 1 1.67 x 10-24 Neutron no 1 1.67 x 10-24 http://www.unit5.org/christjs/site%20map.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.unit5.org/christjs/site%20map.htm

If the atom was the size of a stadium, http://www.andrew.cmu.edu/user/jgrao/Manchester%20United/giant%20stadium.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 X Mass number Atomic # protons + # neutrons mass number # protons http://www.unit5.org/christjs/site%20map.htm

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

F Symbols 19 9 Find the number of protons number of neutrons http://chemistry.beloit.edu/Stars/EMSpectrum/fluorine.gif Symbols Find the number of protons number of neutrons number of electrons Atomic number Mass number = F 19 9 = = = = http://www.unit5.org/christjs/site%20map.htm

F Symbols 19 9 Find the number of protons number of neutrons http://chemistry.beloit.edu/Stars/EMSpectrum/fluorine.gif Symbols Find the number of protons number of neutrons number of electrons Atomic number Mass number = 9 + F 19 9 = 10 = 9 = 9 = 19 http://www.unit5.org/christjs/site%20map.htm

Br Symbols 80 35 Find the number of protons number of neutrons number of electrons Atomic number Mass number = = = Br 80 35 = = http://www.unit5.org/christjs/site%20map.htm

Br Symbols 80 35 Find the number of protons number of neutrons number of electrons Atomic number Mass number = 35 = 45 = 35 Br 80 35 = 35 = 80 http://www.unit5.org/christjs/site%20map.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

Na Symbols 23 11 Find the 1+ number of protons number of neutrons number of electrons Atomic number Mass number = Na = 23 1+ = 11 = = Sodium ion http://www.unit5.org/christjs/site%20map.htm

Na Symbols 23 11 Find the 1+ number of protons number of neutrons number of electrons Atomic number Mass number = 11 Na = 12 23 1+ = 10 11 = 11 = 23 Sodium ion http://www.unit5.org/christjs/site%20map.htm

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