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Atoms and Elements By Jose Andres HernandezGodoy and Mr. Lin Atomic Vocabulary • Ion: A charged atom. Not neutral. There is either more electrons than protons or more protons than electrons. This does not change the element because the same amount of protons exist. – Hydrogen with one proton and one electron is neutral but is not stable. A stable Hydrogen will have two electrons, making it a negative ion. • Isotope: An atom with more or less neutrons. As a result, the atomic mass is affected, but not its atomic number. 2 This is an example of Helium (He). He e Its atomic mass is 4.002 AMU 2 Protons = 2 AMU 2 Neutrons = 2 AMU The remaining 0.002 refer to the mass of the electrons 4.002 P N N e P 3 This is an example of Lithium (Li). e Its atomic mass is 6.941 AMU 3 Protons = 3 AMU 3 Neutrons = 3 AMU The remaining 0.941 refer to the mass of the electrons Li 6.941 P N P N N P e e 5 e This is an example of Boron (B) B e 10.811 Its atomic mass is 10.811 AMU 5 Proton= 5 AMU 5 Neutrons = 5 AMU The remaining 0.811 refer to the mass of the electrons N N P P P N N P N P e e e 1 This is an example of Hydrogen (H) H Its atomic mass is 4.002 AMU 1.00794 1 Protons = 1 AMU 0 Neutrons = 0 AMU The remaining 0.00794 refer to the mass of the electron P e Atoms • Protons: Positive charge • Electrons: Negative charge • Neutron: No charge Image Courtesy of http://tharkad.pa.msu.edu/~asteiner/wpcontent/uploads/atom_model_03.gif • Nucleus: Middle clump of protons and neutrons. This is an example of Carbon (C) 6 e Its atomic mass is 12.0107 AMU C 6 Proton= 6 AMU e 12.0107 6 Neutrons = 6 AMU The remaining 0.00674 refer to the mass of the electrons e N N P P NP P N P P e e e Stable Atoms • An atom will be stable if only its outer shell is completely full. – Hydrogen is not stable because it has only one electron in a shell that can hold up to two electrons. – Lithium is not stable because it has only 1 electron in an outer shell that can hold up to eight electrons. • Hydrogen would typically like to gain an electron to fill up its outer shell. • Lithium would typically like to lose an electron to have a full outershell. Ionic Bond • When a Hydrogen atom meets a Lithium atom, the Lithium atom will lose its outer electron to the Hydrogen. – Neither atom will have a neutral charge. • Hydrogen will have a negative charge now because it now will have more electrons than protons. • Lithium will have a positive charge now because it now will have more protons than electrons. • The next slide demonstrates an ionic bond e P N P N N P P e e e e e P N P N N P P e e Covalent Bond • When two atoms share possession of electrons, they bind in a covalent bond. • When two Hydrogen atoms meet, neither want to give up an electron, but both would like to gain an electron. – As a result, they will “share” their electrons. P P e e e P P e We Are Stable Together !