Mendeleev, the Detective

1. Mendeleev, the Detective • DemitriMendeleev recognized in 1869 that there was a _______________________in elements. • Patterns appeared when the elements were arranged in order of _________________atomic mass and the bonding power.

2. Periodic table • A chart of the elements showing the __________________pattern of their properties.

3. Atomic Number • The number of ____________ in a nucleus • The modern periodic table is arranged according to atomic number.

4. Groups • 18 groups that are arranged in ________________. • Groups are also known as _______________. • Elements in each group have ______________characteristics.

5. Periods • Each horizontal row across the table is called a ___________. • The elements in each period are _________alike.

7. There is a pattern in the periods • From left to right • the periodic table goes from metals to non- metals • from highly reactive to less reactive

8. Valence electrons • Electrons that are involved in _____________________ • Only the electrons that are the farthest out can be __________ or ___________________.

9. Valence electrons • The number of valence electrons determines whether the element _________ up or, __________, or ___________ electrons. • All elements in one group have the ________ number and arrangement of valence electrons. • From left to right Valence number of electrons ________________

11. Molecules Chemical bond involves only Valence electrons

13. Alkali Metals Noble Gases Alkaline Earth Metals Boron Carbon Nitrogen Oxygen Halogens