Structure of ElementsAtomic NumberThe nucleus of an atom contains neutrons and positively charged protons. Neutrons have no charge, but are thought to help to keep the nucleus together. The number of protons in the nucleus is the atomic number of that atom. All atoms of an element have the same atomic number. The atomic number represents the most important property of an element.IsotopesEach element has a limited number of naturally occurring isotopes. Isotopes are different forms of the same atom. An isotope of an element has the same number of protons but a different number of neutrons. Because atomic mass is determined by the number of protons and neutrons in an atom, isotopes of the same element have different masses. Atomic MassScientists express the mass of an atom in atomic mass units (amu). The mass of a proton is about 1 amu. The mass of a neutron, although a bit more massive than a proton is still considered to be 1 amu. The mass of an electron is so small that it is not used in calculating atomic mass. 8 protons8 protons8 protons8 neutrons9 neutrons10 neutrons# of protons(atomic number) # of neutronsAtomic mass(protons + neutrons)888891015.9949 amu16.9991 amu17.9991 amuO8Oxygen15.999valenceshellOxygen atomnucleus123456valenceshellnucleus12345678HydrogenatomHydrogenatomElectron ConfigurationElectrons are negatively charged particles that surround the nucleus in the form of a cloud. The atomic number of an atom, which is equivalent to its number of protons, also represents the number of electrons in that atom. electrons are arranged in an atom is called the . Electrons are distributed among orbital shells or energy levels that are different distances from the nucleus. Electrons that are in the highest or outmost energy level are called valence electrons. The valence electrons are the ones that are lost, gained or shared during chemical bonding. orbital or two electrons. The second energy level can hold up to eight electrons. Oxygen atom (neutral)electronorbital shell 1orbital shell 2atomic number = 8protons = 8electrons = 8electroncloudvalenceelectronnucleus12345768Electrons & BondingOxygen’s valence shell has six electrons but it can hold up to eight electrons. Therefore, oxygen will combine with other elements that allow it to share or lose two electrons. Atoms with four or more electrons in the valence shell like to gain electronsshell. Atoms with three or less electrons in their valence shell like to lose electrons to reveal the full inner shell. Atoms with full valence shells will not combine with other elements.© Copyright NewPath Learning. All Rights Reserved. 94-4848Visit www.newpathlearning.com for Online Learning Resources.element namesymbolatomic numberO8Oxygen15.999protonelectronneutronnucleusOxygen atomweighted average of the masses of isotopesOxygen isotopesThe nucleus of an atom contains neutrons and positively charged protons. Neutrons have no charge, but are thought to help to keep the nucleus together. The number of protons in the nucleus is the atomic number of that atom. All atoms of an element have the same atomic number. The atomic number represents the most important property of an element.EEEEEEEEEEEEEEEEEaaaaaaaaaaaaccccccccccccchhhhh eeeeeeeeeeeelllllllllllllement has a limmmmmmmmmmmmmiiiiiiiiiiiitttttttttttteeeeeeeeeeeedddddddddddddd nnnumberrrrrrrrrrr oooooooooooooooffffffff naturallyoooccuuuuuuuuurrrrrrrrrrrrrrrrrrrrriiiiiiiiinnnnnnnngg isotopes. Isooooooooottttttttttooooooooooooppppppppppppppeeeeessssss aaaaaaaaaaaaarrrrrrrrrrrreeeeeeeeeeeee different forms of tttttttttthhhhhhhhhhhhhhhhhhhheeeeeeeeeee sssssssssssameeeeeeeeee aaaaaaaaaaaattttttttttttoooooooooooom. 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SSSSSSSSSSSSSSSSccccientissssssssssssstttttttttttsssssssssssssss eeeeeeeeeeexxxxxxxxpppppppppppppppppprrrrrrrrrreeeeeeeeeeeeeeeeeesssssssssssssssssssss ttttttttthhhhhhhhhhhhhe mass of an atom in atomic mass uuuuuuuuuuuuuuuuunnits (((((((((((aaaaaaaaaaaammmmmmmmmmmmmmmuuuuuuuu)))))))). TTTTTTTTTTTTTTTTTTTTTTTTThhhhhhhhhhhhhhhheeeeee mass of a proton is about 1 amu. The mass of a nnnnnnnnneeeeeeeeeeeeuuuuuuuuuuuuuuutttttttttttrrrrrroooonnnnnnnnnnnnnn,,,,,,, although a bit more massive than a proton is stilllllllllll ccccccccccccccoooooooooooonsidered to be 1 amu. The mass of aaaaaaaannnnn eeeeeeeeelllllleeeeeecccccccccttttttrrrroooooonnnnnnnn iiiiisssssss ssssssssooooooooo small that it is not used in calculating aaaaaaaaaaaaatttttttttttoommmmmmmmmiiiccccc mmmmmmmmmmmmmmmmmaaaaaaasssssssssss... 8 protons8 protons8 proooottttttttttttoooooooooooonnnnnnnnnnnnnnssssssssssss8 neutrons9 neutrons10 neuuuuuuuuttttttttttttttrrrrrrronnnnsssssssssssppp# of protons(atomic number)pp# of neutronsAtomic mass(protons + neutrons)888891015.9949 amu16.9991 amu17.9991 amuuuuuuuuuuuu8Oxygen11111111111555555555555...99999valennnnnnnnnnnncccccccccccceeeeeeeevvssssshhhhhhhhhhhhhheeeeeeeeeeellllllOxygen atomnucleus123456666666666valencevvshellnucleus12345678HydrogenatomHydrogenatomElectrons are negatively charged particles thhhhhhaaaaaaaaaattttttttt ssssssssssssuuuuuuuuuuurrrrrrrrrrrrrroundddddddddddddd ttttttttttthhhhhhhhe nucleus in the form of a clouddddddddd....... 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EEEEEEEEEEEEEElllllllllllllllllleeeeeeeeeeecctrons arrrrrrrreeeeeeeeeeee ddddddddddddiiiiiiiiissstriiiiiiiibbbbbbbbbbbbbuuuuuuuuuuuted among orbital shells or ennnnnnnnnnnnneeeeeeeeeeeeeergggggggggyyyyyyyyyyyyyyy llllllllllllleeeeeeeeeeeevvvvvvvvvvvveeeeeeeeeeeels ttttttttthhhhhhhhhhhhhhhhhhhaaaaaaaaaaaaaaaattttttttt are diffffeeeeerrrrrrrrrrreeeeeeeeeeeennnnnnnnnnnnnnnttttttttttttt disssssstttttttttttaaaaaaaaaaaannnces frommmmmmmmmmmm the nucleus. Elecccccccctttttttttttttttrrrrrrrrrrronnnnnnnnnnssssssss ttttthat aarrrrrrrrreeeeeeeeeeeeee iiiiiiiinnnnnnnn thhhhhhhhhhhhhheeeeeeeeeeeeee hhhhhhhhhhhhhhhhiigghest or ouuuuuuuuuuutttttttttmmmmmmmmmmmmmmooooooooosssssssssssttttttttttttttttt eeeeeeeeeeeeennnnnnnerrgggggggggggggggggggyyyyyyyyyyyyyyyy level are called vvvvvvvvvvvvvaaleeeeeeeeennnnnnnnnnnnnccccceeeee eeeeeeeeeelllllllllleeeeeeeeeeeeccccccccctronssssss. 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TTTTTTTTTTTTTTTThhhhhhhhhhhhhhhhhhheeeeeeeeeeeeerrrrrrrrrrefore, oxyggggggggggggeeeeeeeeeennnnnnnnnnnn wwwwwwwwwwwwwwiiiiiiiiiiillllllllllllllllllllllllll combine with other eeeeeeeeeeeelllllllllllleeeeeeeeeeeeemmmmmmmmmmmmmmeeennnnnnnnnnnnnntttttttttttttssssssssssss that aaaaaaaaaaalllllllllllllllllllllllooooooooow it to share or lose two elecccctttttttttttrrrrrrrrrrroooooooooooooonnnnnnnnnnnnnss.AAAtoooommmmmmmmmmmmmmsssssssssss wwwwwwwwwwwith four or more electrons in the vvaaaaaaaaaalllllllllllleeeeeeeeeeeennnnnnnnncce sshhhhhhhhhhhhheeeeeeeeeeelllllllllllllllllll llllike to gain electronsshell. AAAAAAAAAAAAAtttttttttttooooooooooooooommmmmmmmmmmmmmmss wiiiiiiittttttttttttthhhhhhhhhhhhhhhhhhhhhh tttttttttttthhhhhhhhhhhhhhree or less electtttrrrrrrrrrrrrrrrrrooooooooooooonnnnnnnnnnnnnnnnnnssssssss iiin their valenceeeeeeeee ssssssssssssssshhhhhhhhhhhhhhhhheeeeeeeeell lllllllliiiiiiiiiiiiiiikkkkkkkkkkkkkkkkkkeeeeeeeeeeeeeeeeeeeeeee tttttttttttttttttttoooooooooooooo lose eeeeeeeeeeeellllllllllllleeeeeeeeeeeeeeecccccccccccccccctttttttttttttttttrrrrrrrrrrrrrooons to reveal the full inneeeeeeeerrrrrrrrrrrrrrrr ssssssssssssssshhhhhhhhhhhhhhhheeell. AAAAAAAAAAAAAAAAttttttttttttttttttooooooooooooooooommmmmmmmmmmmmmms wwwwwwwwwwwwwwwwwwwwwith full valence shells will not cccccccccoooooooooooooooommmmmmmmmmmmmmmmmmmmbbbbbbbbbbbbinnnnnnnnnnnnnnneeeeeeeeeeeeeeeeeeee wwwwwwwwwith other leeeeeeeellllllllleeeeeeeeeeemmmmmmmmmmmeeennnnnnnnnttttttttttt nnnnnnnnnnnaaamesssssssssyyyyyyyyyyyyyymmmmmmmbollllllatommmmmmmmmmiiiiiiccccc nnnnnnnnnuuuuuuuummmmmmmmbbbbbbbbbbbeeeeeeeeeerrrrrrrrrrr8Oxygggeen111111115555555555.999ppppppppppppppppprrrrrrroooooooooooootttttttttttttonelectroooooooooooooonnnnnnnnnnneutttttttttrrrrrrrrrroooooooooooonnnnnnucleusOOOOOOOOOOOxxxxxxxxxxxxyyyyyyyyyyyyyyygggggggggggeeeeeeeeeeennnnnnnnnnnn aaaaaaaaaatommmmweigggggggggggghhhhhhhhhhhhhhtttttttttttteeeeeeeeeeddddd avvvvvvvvvvveeeeeeeeeeeeerrrrrrrrrraaaaaaaaaaaggggggge oooooofffffffffff tttttttttttthhhhhhhhhhhhhhe mmmmmmmmmmaaaaaaaaaaasssssssssssssssssssseeeeeeeeeeesssssssssssss oooooooooooofffffffffff iiiiiiiiissssssssssotooooooooooppppppppppppeeeeeeeeeeeesssssssssssssOxygen isotopes
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