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The Atom & Subatomic Particles. Relative Charge. Relative Mass. electron 0 e. -1. 0.0005486 amu (or 0 amu). - 1. proton 1 p or 1 H. +1. 1.0073 amu (or 1 amu). 1. 1. neutron 1 n. 0. 1.0087 amu (or 1 amu). 0. What we knew by 1932:. Location of Subatomic Particles.
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Relative Charge Relative Mass electron 0e -1 0.0005486 amu (or 0 amu) -1 proton 1p or 1H +1 1.0073 amu (or 1 amu) 1 1 neutron 1n 0 1.0087 amu (or 1 amu) 0 What we knew by 1932:
Location of Subatomic Particles • electrons located outside nucleus • protons & neutrons located inside nucleus
atomic number: = size of nuclear charge = number of protons in nucleus • determines identity of element • gives order to PT • For neutral atoms: atomic number = # protons = # electrons Atomic Number
= # protons + # neutrons Mass Number
atoms of same element can have different mass numbers • # protons must be the same so … # neutrons must be different Isotopes
Dalton’s theory must be modified: • the atom is divisible presence of subatomic particles • atoms of same element can be different isotopes have different # neutrons
12C Notation 6 • left superscript is mass number • left subscript is atomic number
12 = # protons + neutrons 6 = # protons 12C Notation 6 How many neutrons in this atom? 12 – 6 = 6 neutrons
17 8 17 – 8 8 Mass number is ? Atomic number is ? # of neutrons is ? # of electrons in atom is? 17O 8 = 9
15 N 15 7 7 15 – 7 7 Mass number is ? Atomic number is ? # of neutrons is ? # of electrons in atom is? = 8
F 19 9 19 – 9 = 10 9 19 Mass number is ? Atomic number is ? # of neutrons is ? # of electrons in atom is?
C-12 # after symbol is mass number! • must look up atomic number Other Notations
All H’s have 1 proton What’s the difference between H-1, H-2, and H-3? H-1: mass # = 1 0 • 1 proton, ? neutrons H-2: mass # = 2 1 • 1 proton, so it must have ? neutrons H-3: mass # = 3 2 1 proton, so it must have ? neutrons
92 • What’s the atomic number of U? • How many protons in U? • How many neutrons in U-234? • How many neutrons in U-235? • How many neutrons in U-238? • How many electrons in U? Consider U-234, U-235, & U-238 92 234 – 92 = 142 235 – 92 = 143 238 – 92 = 146 92
84 • What’s the atomic number? • How many protons? • So the neutrons are … How many neutrons in Po-217? 84 217 – 84 = 133 neutrons!
IONS = atoms that gained or lost electrons • protons and electrons aren't = anymore, so ions are not neutral they carry a charge (+/-) IONS
Charge of ion: = # protons minus # electrons (subtract the electrons since are negative) IONS
positive negative • If atom loses electrons, it has more (+) protons than (-) electrons • What kind of ion is it? • If atom gains electrons, it has more (-) electrons than (+) protons • What kind of ion is it? IONS
Ion charge: right superscript Cl-1 a chloride ion with a charge of -1 Na+1 a sodium ion with a charge of +1 O-2 an oxygen ion with a charge of -2 If no right superscript, it’s understood to be zero and therefore a neutral atom Charge of Ions
Got 2 e- Lost 1 e- Got 1 e- 19F-1 9 1 16 p, 18 n, 18 e 9 p, 10 n, 10 e 11 p, 12 n, 10 e Lost 2 e- Got 3 e- Lost 2 e- 7 7 p, 6 n, 10 e 30 p, 34 n, 28 e • How many protons, neutrons, & electrons in each of the following 23Na+1 Putting it all together 34S-2 16 13N-3 64Zn+2 25Mg+2 12 30 12 p, 13 n, 10 e
atomic mass unit amu 1/12 the mass of the C-12 atom What is an amu?