1. The Periodic Table J.W. Dobereiner _____________ Groupings of ___ elements with _________________

2. The Periodic Table In the early 1860’s, about ______ elements were known. There was no reliable method for measuring the ____________________ of atoms. Different chemists would find different ___________ were being used to represent the same compound

3. The Periodic Table In September of 1860, at the 1 st International Congress of Chemistry, _________________ _________revealed a method for accurately measuring relative masses of atoms.

4. The Periodic Table 1863 John Newlands creates ____________________ It states that every _____ element in order of increasing atomic mass should have similar properties. This works for some smaller atoms, but does not work as atoms become ____________________

5. The Periodic Table Dmitri Mendeleev He arranged the elements by patterns_________ and by similar properties of elements He noticed that similarities occurred in elements when they were arranged by ____________________ He ____________________ in his table for elements that he thought existed but had not been discovered He could make ____________________ predictions about the properties of these elements

6. The Periodic Table Moseley, who had worked with Rutherford, rearranged the periodic table by increasing numbers of ____________________. This led to using the _____________________as the basis for the organization of the periodic table The Periodic Law The law stating that many of the physical and chemical properties of the elements tend to ____________________ ____________________ with increasing atomic number.

7. The Periodic Table s-block Group 1 The ____________________ ____________________ Not found __________ in nature Have ____ outer electron Tend to lose _____electron in compounds _________ ________. They can be easily cut with a knife Low __________ points ________ reactive toward the bottom of the group

8. The Periodic Table Group 2 The ____________________ Metals Have ___ outer electrons ____________________ ____________________ than Group 1 elements Still very reactive, but _____ reactive than Group 1 elements Not found freely in nature More reactive towards bottom of group

9. The Periodic Table Hydrogen Has ____ outer electron Is sometimes considered to be a _________element and at other times is considered to be its own group It is a _____ at room temperature If frozen until solid, hydrogen is a _______ _____% of the atoms in the universe are hydrogen atoms _____% of the mass of the universe is hydrogen

10. The Periodic Table Helium A stable and filled _________________ ___ places it with the noble gases even though it has only 2 outer electrons. _____% of the mass of the universe is helium

11. The Periodic Table d-block Transition Elements Sometimes called the transition ______ Groups _______ All are ______ Generally ____________________ ____________________ when compared to s-block elements _______ as reactive as s-block elements Some can be found _______ in nature Tend to have _______ outer electrons Tend to lose ________ electrons in compounds Cause colors in ______________ as impurities in crystal structures

12. The Periodic Table p-block Groups ________ ______________ elements-elements in the s and p blocks Have _____ outer electrons Elements with 4 or more electrons normally ________ or ______ electrons in compounds ______________ are found in this region

13. The Periodic Table Group 17 The Halogens ______________ ______________ is the most reactive element ___ outer electrons Gain ___ electron to achieve a structure like a noble gas The word halogen means “______________”

14. The Periodic Table Group 18 Noble Gases ______________ due to filled and stable outer energy level Very few compounds can be made with ___, ___, and ___. There are no known compounds using ___, ___, or ___

15. The Periodic Table Helium- 1868 ______________ discovered it in solar spectra ______________ confirmed helium on earth in 1895 Neon- 1898 discovered by ______________ Argon-1894 discovered by ______________ and ________________________ Krypton-1898 _____________ Xenon-1898 ______________ Radon- 1900 ________________________

16. The Periodic Table Lanthanides Mostly discovered in __________ Elements ________ Also called ___________________________ _ They comprise less than ____% of the earth’s crust Actinides Elements ______ All are ______________ Elements above 92, Uranium, are ______________ ______________ elements- synthetic elements that are past Uranium, the last of the naturally occurring elements on the periodic table

17. Periodic Trends Atomic Radii ______________ across a period As the number of _______ increases in atoms across a period, the attractive forces of the nucleus on the electrons in the atom also increase. This increase in ______________ allows the nucleus to pull electrons closer to the nucleus, making for _______atoms. ______________ down a family Every new family adds an ______________ where electrons can reside. As more energy levels are added, each outer orbital is ___________ from the nucleus than the last.

18. Periodic Trends Ionic Radius Cations Cations are ___________ ions Metals tend to ______ electrons and become cations Cations are ________ than the neutral atom The _____ amount of force pulls on electrons regardless of how many electrons are present in a given atom. The removal of electrons _____________the amount of pull that is distributed among the remaining electrons, holding the electrons __________ to the nucleus. Anions Anions are ___________ ions ______________ tend to form anions Anions are _________ than the neutral atom The same amount of force pulls on electrons regardless of how many electrons are present in a given atom. If electrons are added to the atom, the electrons each feel ______ nuclear pull than they did in the neutral atom and move ______________ from the nucleus, __________________ the atomic radius.

19. Periodic Trends Valence electrons Electrons found in the____________sublevels of the outermost energy level Atoms will gain or lose enough electrons to have an ________ Metals will lose electrons to have an electron configuration like the ______________, becoming cations Nonmetals will gain electrons to have an electron configuration like the _______________, becoming anions The Electron Dot structure shows how many _________ electrons an atom has and how many it will gain or lose as it becomes an ion

20. Periodic Trends Electronegativity The measure of an atom’s ability to _____________________in a compound The lowest value is ______(Cs,Fr) The highest value is ______(F) Electronegativity __________ across a period because atoms that tend to gain electrons to become ions will also attract electrons when in a compound Electronegativity _____________ down a family because atoms that are larger are not as effective at attracting electrons because of the distance that outer electrons will be from the nucleus

21. Periodic Trends Ionization Energy The energy required to ___________________________ from an atom Each electron that is removed results in the next electron being ___________________to remove because each remaining electron is held more tightly. A huge ___________ in the energy required for removing electrons occurs when the atom’s electron configuration is the same as a ______________. Ionization Energy _____________ across periods Ionization Energy _____________ down a family

22. Periodic Trends Shielding Effect ________ electrons block some of the ______________ on outer electrons, making them __________ to remove Shielding effect is ________ across a period since no new energy levels are added to the atom Shielding effect____________down a family because new energy levels of electrons are added with each new row on the periodic table

23. Periodic Trends Electron Affinity The energy change when a neutral atom ______________ an electron Can be ______________ (absorbing energy) or ______________ (releasing energy) Electron Affinity ______________ across a period Electron Affinity ______________ down a family

24. Periodic Trends