1 / 12

The Periodic Table

The Periodic Table. Organizing the Elements. Purpose of the Periodic Table. To organize the elements based on similar properties Makes them easy to study, easy to predict patterns, easy to reference. Mendeleev. 1869, Russian scientist, Dmitri Mendeleev, saw hidden patterns in the elements .

misha
Download Presentation

The Periodic Table

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 Periodic Table Organizing the Elements

  2. Purpose of the Periodic Table • To organize the elements based on similar properties • Makes them easy to study, easy to predict patterns, easy to reference

  3. Mendeleev • 1869, Russian scientist, Dmitri Mendeleev, saw hidden patterns in the elements . • Looked at similar chemical and physical properties. • Ex: silver and copper both tarnish in air • Fluorine and chlorine both toxic gases when breathed

  4. First periodic table • Mendeleev wrote down all properties of the elements, including atomic mass and bonding power. • Atomic mass – average mass of one atom of the element. • Bonding power – number of chemical bonds an element can form.

  5. First Periodic Table • Patterns appeared when the elements were arranged in order of increasing atomic mass. • Bonding power also changed in an orderly way. • Left blank spaces for elements he felt had not been discovered yet. Predicted their properties. • Periodic – regular, repeated pattern • Mendeleev published the 1st periodic table in 1869.

  6. The Table and Atoms • What we know about atoms changed the periodic table • Atoms are made of protons and neutrons in the nucleus, electrons orbit the nucleus. • Atomic mass unit – the mass of one proton.

  7. Atoms • AMU’s – used to measure the mass of atoms of the elements. • Example: Helium • Atomic mass = 4 • (2 protons, 2 neutrons) • Electrons have almost no mass • Neutral atom – means equal number of protons and electrons.

  8. Atomic Number • Every atom of an element has the same number of protons. Defines that element. • Atomic number = # of protons • Table organized by atomic number

  9. Trends in the Table

  10. Trends in Table • Elements in a column are called a group, or family. Often given a family name. • Families have similar characteristics. • Ex: Alkali metals, 1st family – highly volatile, same atomic structure. • Horizontal rows – called periods.

  11. Valence Electrons • Valence electrons – number of electrons in the outer layer around the nucleus • These electrons are responsible for bonding. • Determines the bonding power of an element. • Groups or families all have the same # of valence electrons.

More Related