the atom & subatomic particles. atomic number  atomic number: = size of nuclear charge = size of...

Download The Atom & Subatomic Particles. Atomic Number  atomic number: = size of nuclear charge = size of nuclear charge = number of protons in nucleus = number

Post on 23-Dec-2015

212 views

Category:

Documents

0 download

Embed Size (px)

TRANSCRIPT

  • Slide 1
  • The Atom & Subatomic Particles
  • Slide 2
  • Atomic Number atomic number: = size of nuclear charge = size of nuclear charge = number of protons in nucleus = number of protons in nucleus determines identity of element determines identity of element used to give order to periodic table used to give order to periodic table For neutral atoms: atomic number = number of electrons atomic number = number of electrons
  • Slide 3
  • What is an atom?
  • Slide 4
  • Number of Protons = Number of Electrons Number of Protons = Atomic Number Atomic Mass = Protons + Neutrons
  • Slide 5
  • What we knew by 1932: 1.0087 amu (or 1 amu) 0 Neutron, 1 n 1.0073 amu (or 1 amu) +1 Proton, 1 p or 1 H.0005486 amu (or 0 amu) Electron, 0 e Relative Mass Relative Charge 11 0
  • Slide 6
  • Location of Subatomic Particles Electrons located outside nucleus Electrons located outside nucleus Protons & neutrons located inside nucleus Protons & neutrons located inside nucleus Protons & neutrons = nucleons Protons & neutrons = nucleons
  • Slide 7
  • Isotopes atoms of same element with different # neutrons (mass # is different) different # neutrons (mass # is different) # protons stays same! (atomic # is same) # protons stays same! (atomic # is same) Daltons theory modified in number of important ways: the atom is divisible (protons, neutrons, electrons) the atom is divisible (protons, neutrons, electrons) atoms of same element can be different (different # neutrons) atoms of same element can be different (different # neutrons)
  • Slide 8
  • Mass Number Mass number = # protons + # neutrons
  • Slide 9
  • Notation 12 C 6 left superscript is mass numberleft superscript is mass number left subscript is atomic numberleft subscript is atomic number
  • Slide 10
  • Notation 12 C 6 12 = # protons + neutrons 6 = # protons 6 = # protons 12 6 = 6 neutrons How many neutrons in this atom?
  • Slide 11
  • 17 O 8 Mass number is ? Atomic number is ? # of neutrons is ? # of electrons in atom is? 17 8 17 8 = 9 8
  • Slide 12
  • Mass number is ? Atomic number is ? # of neutrons is ? # of electrons in atom is? 15 N 7 15 7 15 7 = 8 7
  • Slide 13
  • Mass number is ? Atomic number is ? # of neutrons is ? # of electrons in atom is? 19 F 19 9 19 9 = 10 9
  • Slide 14
  • Other Notations Might also see: C-12 number following symbol is mass number! number following symbol is mass number! Need to look up atomic number
  • Slide 15
  • Whats the difference between H-1, H-2, and H-3? All Hs have 1 proton H-1: mass # = 1 1 proton, 0 neutrons 1 proton, 0 neutrons H-2: mass # = 2 1 proton, so it must have 1 neutron 1 proton, so it must have 1 neutron H-3: mass # = 3 1 proton, so it must have 2 neutrons 1 proton, so it must have 2 neutrons
  • Slide 16
  • Consider U-234, U-235, & U-238 Whats 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? 92 92 234 92 = 142 235 92 = 143 238 92 = 146 92
  • Slide 17
  • How many neutrons in Po-217? Whats the atomic number? How many protons? So the neutrons are 84 84 217 84 = 133 neutrons!
  • Slide 18
  • IONS Atoms: electrically neutral so... # electrons = # protons # electrons = # protons IONS = atoms that gained or lost electrons protons and electrons aren't = anymore, so ions are not neutral they carry a charge (+/-)
  • Slide 19
  • IONS Charge of ion: = # protons minus # electrons (subtract the electrons since are negative)
  • Slide 20
  • IONS If atom loses electrons, it has more positive charge than negative What kind of ion is it? What kind of ion is it? If atom gains electrons, it has more negative charge than positive What kind of ion is it? What kind of ion is it?positive negative
  • Slide 21
  • Charge of Ions Ion charge written as 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, its understood to be zero and therefore a neutral atom
  • Slide 22
  • Putting it all together How many protons, neutrons, & electrons in each of the following 23 Na +1 1 25 Mg +2 12 34 S -2 16 64 Zn +2 30 11 p, 12 n, 10 e 12 p, 13 n, 10 e 16 p, 18 n, 18 e 30 p, 34 n, 28 e Lost 1 Got 2 Lost 2
  • Slide 23
  • What is an amu? equal to the atomic mass unit amu 1/12 the mass of the C-12 atom C-12 is used as the reference for atomic mass
  • Slide 24
  • Atomic Weight or Mass Atomic mass is relative 1 st H-1 used as standard: 1 atom of H = 1 amu 1 atom of H = 1 amu next O-16 used as standard: O combines with many elements O combines with many elements 1 atom of O = 16 amu's 1 atom of O = 16 amu's Now C-12 is the standard: 1 atom of C-12 has a mass of exactly 12 amu's 1 atom of C-12 has a mass of exactly 12 amu's

Recommended

View more >