Electrons Chemistry Dr. May

Atomic Inventory Protons (Atomic Number) Neutrons (Atomic Mass minus Protons) Electrons (Same number as protons)

Atomic Particles ParticleLocationMass in amu Charge Proton Neutron Electron nucleus cloud  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 1s2s 2p3s 3p4s Ca - 40  EC 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2

Electron Configuration Krypton –1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 Sodium –1s 2 2s 2 2p 6 3s 1 Chlorine –1s 2 2s 2 2p 6 3s 2 3p 5

Reading Electron Configurations Krypton - 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 The large numbers are the orbitals and in the known elements can go from 1 to 7

Reading Electron Configurations Krypton - 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 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 - 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 The superscript or exponent (2p 6 ) represents the number of electrons in each suborbital Kr has 6 electrons in the 2p

Valence Electrons Krypton - 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 has 8 valence electrons Sodium - 1s 2 2s 2 2p 6 3s 1 has 1 valence electron Chlorine - 1s 2 2s 2 2p 6 3s 2 3p 5 has 7 valence electrons

Element 118 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 6s 2 4f 14 5d 10 6p 6 7s 2 5f 14 6d 10 7p 6 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 Ca = 2 Al = 3 C = 4 N = 5 O = 6 Cl = 7 Ne = 8

Oxidation Number Number of valence electrons lost (+) or gained (–) during a chemical reaction Na = (1) +1 Ca = (2) +2 Al = (3) +3 C = (4) +4 or –4 N = (5) +5 or –3 O = (6) –2 Cl = (7) –1 Ne = (8) 0

Distribution Of Sodium atom 1s2s 2p3s 3p4s Na - 11  

Distribution Of Sodium Ion ion 1s2s 2p3s 3p4s Na +1  X

Distribution Of Chlorine atom 1s2s 2p3s 3p4s Cl - 17  

Distribution Of Chloride Ion ion 1s2s 2p3s 3p4s Cl  1  

Opposite Charges Attract

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