1 / 24

The History of the Periodic Table and trends

The History of the Periodic Table and trends. In the olden days…. Many elements were known in the ancient world- copper, gold, silver, lead, etc. For several hundred years, elements were discovered by alchemists. Alchemy was the ultimate search for wisdom and immortality.

zoe
Download Presentation

The History of the Periodic Table and trends

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. The History of the Periodic Tableand trends

  2. In the olden days… • Many elements were known in the ancient world- copper, gold, silver, lead, etc. • For several hundred years, elements were discovered by alchemists • Alchemy was the ultimate search for wisdom and immortality. • Main Goals included: • Transmutation: turning common metals into gold • The creation of an “elixir of life”: to cure all diseases, and prolong life. • The Search for the “Philosopher’s Stone”: give everlasting life and ultimate wisdom

  3. By 1860, more than 60 elements had been discovered….HOWEVER, • There was no consistent organization of the elements. • No one was using the same method to determine mass of atoms, or the ratios of atoms in compounds(how many oxygen atoms and hydrogen atoms in water, for example)Why was this, do you think? • In 1860, Stanislao Cannizzaro of Italy presented a convincing method to measure the mass of atoms, thus creating standard values for atomic mass. Now that there are some common standards…

  4. The Matter of Mendeleyev • In 1869, begins to try to arrange the elements. Inspired by solitaire, he starts to find patterns in the properties of elements, and arranges the known elements in a Periodic (repeating) Table. • Born in 1834, the youngest of 14 (or 17) children

  5. Mendeleev’s Genius • Mendeleev recognized there were undiscovered elements. • By using his periodic table, he could predict the chemical properties of the undiscovered elements.

  6. Henry Moseley • 1911, Moseley (working under the direction of Rutherford(remember him?)Rearranged the Periodic Table to go horizontally, and order the elements by atomic number.

  7. The periodic table when organized by s, p, d, and f, orbitals

  8. The Mayan Periodic Table of Elements by Mitch Fincher A Spiral Periodic Table by Prof. Thoedor Benfey Variations on the Periodic Table

  9. The future of the periodic table?

  10. Periodic Trends • Now that the periodic table is organized, what patterns can we find? • What does it even mean to be ‘periodic’?

  11. Thanks, to Moseley, we learn that patterns arise because of PROTONS!!! • This leads to the development of the Periodic Law: the physical & chemical properties of the elements are periodic functions of their atomic numbers. ** In other words, when the elements are arranged in order of increasing atomic number, elements with similar properties appear at regular intervals.

  12. Pattern: Families • Elements in column share similar traits, and are called families: • These columns are also called groups. Families- alkali metals (column1), alkali-earth metals (column2), transition metals, Nonmetals- boron family, carbon, nitrogen, oxygen family, halogens, noble gases.

  13. The Alkali Metals • 1 valence electron • Highly reactive with water • Form ionic compounds • Do not occur in nature as pure elements (always in compounds)

  14. Alkali-Earth Metals • Have 2 valence electrons • Reactive, but less reactive than alkali metals • Are ductile, malleable and have a silvery luster

  15. Transition metals… and inner transition metals • Are less reactive than groups 1 and 2. • Tend not to react in water. • Are malleable and ductile, but still harder than group 1 & 2. • Tend to be solids at room temperature. • Have variable chemical properties • Are good conductors of electricity and heat. • Inner transition metals tend to be radioactive

  16. Nonmetals • Poor conductors of heat and electricity • Often are found as gases or liquids, sometimes solids.

  17. Are nonmetals highly reactive with metals- most reactive is flourine, lease reactive is astatine Mostly exist as gases or liquids (except At -solid) Have 7 valence electrons Halogens

  18. At room temperature, exist as gases. Are completely unreactive Have full s and p orbitals Are odorless, colorless, nonflammable Noble gases

  19. Tend to be solids Have properties similar to both metals and nonmetals Tend to be semiconductors (which means they are useful for technological uses) Metalloids

  20. Patterns and trends tend to follow the Representative Elements.

  21. Valence Electrons The outermost s & p electrons

  22. The radius of an atom. DIFFERENT from the mass of an atom Atomic Size • Why does an atom get smaller as you move from left to right? The nucleus exerts greater control on the electrons within the energy level

  23. The energy required to LOSE an electron to another atom Ionization Energy • Why would an atom want to lose an electron? • As you get closer to the noble gases, it becomes MORE difficult to lose an electron, so the Ionization Energy gets BIGGER

  24. As electrons get closer to the noble gases, they INCREASE in EN. As electrons go down the P.T, there is a DECREASE in EN. Noble gases have ZERO electronegativity The ability of an atom to TAKE AWAY an electron from another atom Electronegativity

More Related