ch 11 introduction to atoms. the beginning of atomic theory democritus & aristotle can you cut a...
TRANSCRIPT
- Slide 1
- Ch 11 Introduction to Atoms
- Slide 2
- The Beginning of Atomic Theory Democritus & Aristotle Can you cut a piece of paper in half and cut those halves in half and continue until you are left with 1 particle? If you could do this you would end up with what Democritus called an _________= ______________________ Aristotle _____________ with democrituss idea. He believed that ___________________________________ Who was correct? Aristotle or Democritus??
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- The Beginning of Atomic Theory ____________________was correct! Matter is made of particles which we call ___________. Atom -
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- The Beginning of Atomic Theory Dalton 1803 Daltons atomic theory was based on _________________! All substances are made of ______ Atoms are small particles that cannot be _____, _______, or _________. Atoms of the same element are _________ and atoms of different elements are _________. Atoms join with other atoms to make _____ substances.
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- The Beginning of Atomic Theory New information didnt quite fit with _______ ideas. His atomic theory had to be _________. Thomson- 1897 Discovered the ____________ charged particles There are __________ inside the atom. Atoms can be broken down further. (Dalton thought atoms were solid spheres so hes wrong)
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- CATHODE-RAY TUBE A positively charged plate was attracted to a ______. Therefore, the beam must be made up of ________ charges. Thomson concluded these negative charges are _______ in every kind of _______.
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- The Beginning of Atomic Theory ________- A subatomic particle that has a negative charge. Thomson described his model of the atom like plum pudding. Today you might call it the ______________ _____ model. (with electrons represented by _________________.)
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- The Beginning of Atomic Theory Rutherford- 1909 Rutherford was a _____________ of Thomsons. He tried to help prove Thomson theory was _______ and ended up proving him ______! He aimed a beam of small, _________________ ( particles) at a thin piece of gold foil. Photo paper behind the gold recorded where the charged particles hit. Surprising Results He thought the particles would _______________ the gold in a straight line. Some particles were ________. Some shot right ______.
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- Rutherfords Gold-Foil Experiment Rutherford determined an atom must be mostly ______ ______ with a tiny part made of highly dense material.
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- Rutherfords Model ________ The centrally located, tiny, extremely dense positively charged part of an atom.
- Slide 11
- The Beginning of Atomic Theory Bohr 1913 Niels Bohr proposed that electrons move around the nucleus in _______________________________. Electrons can jump from path to path but cannot exist in _____________ paths. Think of ________ on a ladder. You can stand on the rungs, but not ________ the rungs. Or think of planets in our solar system they do not stray off the set path or ___________.
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- The Modern Atomic Theory Schr dinger and Heisenberg Electrons ________ travel in definite paths as Bohr suggested. The exact path of the electron ______ be predicted. There are regions where it is likely to be found called ______ __________.
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- 4.2 The Atom How small is an _____? A penny contains __________ atoms. (20,000,000,000,000,000,000,000 atoms) An atom is made up of _______, _______, and _________. The Nucleus Protons The mass of protons are measured in atomic mass units (amu). Each proton has a mass of __________ _________- Particles in the nucleus that have ___ electrical charge. Neutrons have a mass of 1 amu. (Same as _________)
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- The Atom Outside the nucleus _________ are found outside the nucleus. They have a _______ charge. They have a mass of almost _____. If the number of protons __________ the number of electrons, the atom is ______________
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- HOW DO ATOMS OF DIFFERENT ELEMENTS DIFFER? Atoms of different elements have different numbers of ____________. No two elements have the same _____________. Atomic number is the number of ________ in an atom. All atoms of the _____________ have the _________ atomic number.
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- HOW DO ATOMS OF DIFFERENT ELEMENTS DIFFER? So how do we figure out the number of neutrons for an atom? The number of _____________ = the number of _______________ Mass number The mass number does not include the mass of ____________ because they are so ___________and have very little effect.
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- HOW DO ATOMS OF DIFFERENT ELEMENTS DIFFER? Where do you find these numbers? On the ____________________ ! C C C # of neutrons = _________ - _________ # of neutrons in C = ____ - ____ C P + = N o = E - = ______ # __ + # __ # __ ___
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- HOW DO ATOMS OF DIFFERENT ELEMENTS DIFFER? Mass #Atomic #ProtonsNeutronsElectrons Li Be B C N O F Na k
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- DRAWING BOHR MODELS OF ATOMS Draw the nucleus and label with #p & #n Draw electron orbitals 1 st orbital can have ______ electrons only 2 nd and 3 rd ring can each have ______electrons Fill _____________________ Inner rings must be filled first before any electron enters a higher ring!!!!! Examples:
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- Changing Atoms If you change a persons hair color does it change who they are? Weight? What subatomic particle determines an atoms identity?___________ Therefore, the number of electrons and neutrons can change in the atom and it is still the same atom. If the number of protons __________ the number of electrons, the atom is ______________ If the number of protons ___________ the number of electrons, the atom becomes charged and we call it an _______. Positively charged ions Negatively charged ions -
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- ISOTOPES _________- Atoms that have the same number of protons, but have different numbers of neutrons. Examples: Hydrogen -1 and Hydrogen -2 Naming Isotopes Write the __________ of the element, followed by a hyphened and the _____________________ of the isotope. Ex. A hydrogen atom with 1 proton and 0 neutrons A hydrogen atom with 1 proton and 1 neutron
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- ISOTOPES Mass Number The sum of the _________________ in an atom. (__________ are not included.) Mass # = protons + neutrons Atomic Mass The _____________ of the masses of all the ___________ occurring isotopes of that element.
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- Solving the Atomic Mass Ex: Skittles consist of Orange 1 which is 25% of the Skittles and Red 2 which is 75% of skittles. Step1: change percents to decimals. Step 2: multiply the decimal by the mass Step 3: add the two answers together
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- Solving for Atomic Mass Ex: Chlorine-35 which is 76% of the Chlorine atoms and Chlorine-37 which is 24% of Chlorine atoms. Step1: change percents to decimals. Step 2: multiply the decimal by the mass Step 3: add the two answers together