1 / 14

Dalton

Dalton. Matter is made up of atoms Atoms cannot be divided into smaller pieces All atoms of an element are exactly the same Different elements are made of different kinds of atoms “marble” – hardsphere. Crookes. Anode – positive charge Cathode – negative charge Cathode Ray Tube – CRT

conan-woodard
Download Presentation

Dalton

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Dalton • Matter is made up of atoms • Atoms cannot be divided into smaller pieces • All atoms of an element are exactly the same • Different elements are made of different kinds of atoms • “marble” – hardsphere

  2. Crookes • Anode – positive charge • Cathode – negative charge • Cathode Ray Tube – CRT • Used for TV/ Computer screens

  3. J.J. Tomson • Added a magnet to Crookes cathode ray • Cathode rays are negative charged particles of matter. Now called – Electrons • Particles smaller than an atom exist. • Model – sphere with positive and negative charged particles – “raisin cookie”

  4. Rutherford • All of the mass of the atom and all of its positive charge are crammed into a very small space at the center of the atom – nucleus. • Model Nucleus Protons and neutrons Electrons

  5. Bohr • Negatively charged particles are attracted to positively charged particles. • Electrons travel in orbits around the nucleus. • Energy levels

  6. Rutherford – Bohr Model Protons and neutrons electrons Electron cloud

  7. Atoms • Atoms are basic particles from which all matter is made. • An atom is the smallest part of an element. • 3 main parts of an atom • Proton + • Electron – • Neutron O • Atomic mass = protons + neutrons • # of protons = # of electrons

  8. Isotopes • Every atom of the same element has the SAME number of PROTONS. • However , the number of NEUTRONS can be different for one element. • These are called ISOTOPES – atoms of the same element that have different number of neutrons. • The atomic mass of each isotope differ, because of the number of neutrons. • How many boys named Jack are there in 8th grade?

  9. Periodic Table • Periodic Table classifies elements • Dmitri Medeleev – 1869 • Russian scientist that devised the Periodic Table we use today • Organized by atomic number. • Atomic number = # of protons • Atomic Mass = # of protons + neutrons • Periods • Groups

  10. Classification • Metals – shiny, metallic luster, good conductor of heat and electricity • Nonmetals – brittle, dull, poor conductors of heat and electricity, many are gases at room temp. found in human body • Metalloids - have characteristics of both metals and nonmetals, all are solids at room temp. some are good conductors but not as good as metals

  11. Molecule • Molecule – a group of atoms that are joined together and act as a single unit. • The force that holds 2 atoms together is called a chemical bond. • From the chemical formula you can tell what elements are present in a molecule of that compound.

  12. Element, Compound, Mixture • Elements – made of one substance (Symbol) Ex: Carbon • Compounds – made of 2 or more elements chemically joined (Formula) Ex: Water • Mixture – made of several substances ( no symbol or formula) Ex: Air

  13. Mixtures • Homogeneous Mixtures – the same throughout • Heterogeneous Mixtures – has different parts • Solution – a homogeneous mixture that forms when one substance dissolves in another. • Solvent – does the dissolving • Solute – the substance dissolved • Emulsion – mixture of two liquids that will separate after standing. • Colloid – mixture containing solid particles that are small enough to remain suspended in the liquid but will reflect light.

  14. Mixtures • Tyndall Effect – particles that are very small (can’t be seen by the naked eye) but can reflect light.

More Related