Periodic Table. User-Defined Placeholder Text

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1 Periodic Table User-Defined Placeholder Text

2 History Dalton s Atomic Theory prodded some of knowledge along in regards to understanding atoms (1800 s) What they knew at the time Atomic weights and properties of the elements were known suggestion was that there was some kind of relationship there, but unsure what it was

3 In the Beginnings of the Periodic Table Johann Doberiner showed that then certain elements were grouped in threes, the atomic weights and properties of the middle element were close to the average of the other two He also recognized that the three also had similar properties

4 John Newlands 1863 showed that lighter elements were arranged in order of their increasing atomic weights, there was a repetition of properties in every eighth element He related it to music

5 Lothar Meyer 1864 showed in graphic form a periodic recurrence of certain properties of the elements with increasing atomic weights. He failed to publish his findings

6 Dimitri Mendeleyev 1869 He published his findings He arranged the elements in order of increasing atomic weights but he concluded that there were some elements yet to be discovered So he left blanks and predicted the properties of those missing elements

7 Periodic Law This idea became known as the periodic law Elements are arranged in order of their increasing atomic weights and they show a periodic repetition of properties That is how he was able to predict the properties of the missing elements. This is a fundamental law of nature Gallium and Germanium

8 Henry G. Moseley Mendeleev had organized the elements by the Atomic Weights There were minor problems with the order of the atomic weights Moseley in 1913 studied the elements by X-ray spectra He noticed a regular shift in the position of the lines He reorganized the periodic table by atomic number

9 Arrangement The atomic numbers also re-enforced the idea of the periodic law chemical properties are determined by the number of electrons in the outside shell (valence electrons) The atomic number is determined by the number of protons Atomic weight is the number of protons and neutrons

10 Orderly Arrangement of Properties Many properties reappear in the list of elements is due to the arrangement by the atomic number. Chemical Properties Are determined by the total number of electrons outside the nucleus and more by the valence electrons Atomic numbers are determined by the number of protons

11 Remember Atomic mass is the most massive part of the atom it contains the protons and neutrons electrons are little bitty in size compared to the protons and neutrons the number of protons determine the element

12 Remember also Isotopes are different number of neutrons and NOT PROTONS The Neutrons have no charge! However they do have almost equal mass to that of a proton

13 Modern Periodic Table Symbol- gives the shorthand name of the element Atomic Number- Number of protons Atomic Mass Unit- Decimal number- number of protons and neutrons Rows- Give us how many rings or orbitals are needed Boxes across- Gives us the number of electrons for that ring

14 General Trends of the Periodic Table As you move down the periodic table- the activity of the elements increase (Group 1 and 2) As you move across the periodic table the metallic properties decrease (Group 1-Group 8) As you move down in Group 6 and 7 the activity decreases and the metallic properties increase Group 8 has no Chemical Properties

15 Properties of the Groups We need to make sure that we know each group. Also we need to recognize some vocabulary noble gases representative elements transition metals inner transition metals

16 Electron Configeration Now we will use the s,p,d,f in order to name the elements in another way We will practice filling