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Electrons Chemistry Dr. May Atomic Inventory • Protons (Atomic Number) • Neutrons (Atomic Mass minus Protons) • Electrons (Same number as protons) Atomic Particles Particle Proton Neutron Electron Location Mass in amu Charge nucleus 1 +1 nucleus 1 0 cloud 0 1 Electron Function • Only the electrons of an atom are involved in chemical reactions • Only the electrons in the outermost orbital are involved in chemical reactions Outermost Electrons • Atoms have between 1 and 8 electrons in the outermost orbital • These electrons are called valence electrons • Only valence electrons are involved in chemical reactions Electron Distribution and Configuration Atom 1s Ca - 40 EC 1s2 2s 2p 3s 3p 4s 2s2 2p6 3s2 3p6 4s2 Electron Configuration • Krypton – 1s22s22p63s23p64s23d104p6 • Sodium – 1s22s22p63s1 • Chlorine – 1s22s22p63s23p5 Reading Electron Configurations • Krypton - 1s22s22p63s23p64s23d104p6 • The large numbers are the orbitals and in the known elements can go from 1 to 7 Reading Electron Configurations • Krypton - 1s22s22p63s23p64s23d104p6 • The letters s,p,and d represent the suborbitals • The fourth letter f is not used in Kr Suborbitals • The suborbitals (s,p,d and f) are named after lines in the electromagnetic spectrum: s = sharp p = principle d = diffuse f = fundamental Metal Salts Burning Reading Electron Configurations • Krypton - 1s22s22p63s23p64s23d104p6 • The superscript or exponent (2p6) represents the number of electrons in each suborbital • Kr has 6 electrons in the 2p Valence Electrons • Krypton - 1s22s22p63s23p64s23d104p6 has 8 valence electrons • Sodium - 1s22s22p63s1 has 1 valence electron • Chlorine - 1s22s22p63s23p5 has 7 valence electrons Element 118 • 1s22s22p63s23p64s23d104p65s24d105p66s24f14 5d106p67s25f146d107p6 • Element 118 (ununoctium) (Uuo) • • • • Has 118 electrons Has 8 valence electrons Is an inert gas Was discovered at Berkley in 1999 Valence Electrons Sum of the outermost s an p electrons • Na = 1 • N=5 • Ca = 2 • O=6 • Al = 3 • Cl = 7 • C=4 • Ne = 8 Oxidation Number Number of valence electrons lost (+) or gained (–) during a chemical reaction • Na = (1) +1 • N = (5) +5 or –3 • Ca = (2) +2 • O = (6) –2 • Al = (3) +3 • Cl = (7) –1 • C = (4) +4 or –4 • Ne = (8) 0 Distribution Of Sodium atom Na - 11 1s 2s 2p 3s 3p 4s Distribution Of Sodium Ion ion Na+1 1s 2s 2p 3s X 3p 4s Distribution Of Chlorine atom Cl - 17 1s 2s 2p 3s 3p 4s Distribution Of Chloride Ion ion Cl 1 1s 2s 2p 3s 3p 4s Opposite Charges Attract The End • This presentation was created for the benefit of our students by the Science Department at Howard High School of Technology • Please send suggestions and comments to [email protected]