1. Organizing the Elements

2. Dmitri Mendeleev
-discovered set of patterns that applied to all elements
-1869 published 1st periodic table
-total of 63 elements discovered
-wrote properties of each on note cards (density, color)
-noticed pattern when he arranged them in order of increasing atomic mass

3. Atomic Mass Periodic Table -average mass of all isotopes of an element
-properties of elements repeat in each row of table

5. Henry Moseley
-1913, discovered how to measure protons = atomic number
-table rearranged by atomic number

6. -series of different elements (like days in a week)
-horizontal rows
-series of different elements (like days in a week)
-18 vertical columns
-elements with similar characteristics
-includes:
atomic number
chemical symbol
name
atomic mass
Periods
Groups/Families
Element Squares

7. Chemical Symbol
Average Atomic Mass
-one or two letters representing an element
-abbreviations of English and Latin names
-most elements consist of mix of isotopes
-determined from combined percentages of all isotopes

9. Metals

10. Metal -shininess, malleability, ductility, conductivity
-characterized by physical properties
-shininess, malleability, ductility, conductivity
-some are magnetic: iron (Fe), nickel (Ni)
-most are solid at room temperature, except mercury (Hg) - liquid

11. Malleable
Ductile
Conductivity
hammered/
pounded into shapes
-pulled out into wires
-ability to transfer heat or electricity to another object

12. Reactivity
-chemical property
-ease at which an element reacts with other elements/compounds
-usually react by losing electrons
-↓ from highly reactive to less reactive as you move left to right across table

13. -wearing away of metal
-due to chemical reaction
-group 1
-loses one electron
-extremely reactive
-never found uncombined in nature, only in compounds
Corrosion
Alkali Metals

14. -when pure: shiny and very soft (cuts with plastic knife)
Alkali Metals
-when pure: shiny and very soft (cuts with plastic knife)
-sodium (Na) and potassium (K) important for life
*salt, foods
-lithium (Li)
*batteries, medicines

15. Alkaline Earth Metals -group 2 -loses two electrons
-fairly hard, gray-white
-good conductors
-very reactive
-never found uncombined
-magnesium (Mg)
plus aluminum = light weight material used for ladders, wheels, planes
-calcium (Ca)
essential for bones, teeth
in milk, dairy, green veggies

16. Transition Metals
-groups 3-12
-iron (Fe), copper (Cu), silver (Ag)
-most hard and shiny
-all good conductors of electricity
-less reactive than groups 1 and 2

17. Metals in mixed groups
Lanthanides
-groups 13-15
-not very reactive
-aluminum (Al), tin (Sn), lead (Pb)
-top row at bottom of table
-soft, malleable, shiny, high conductivity
-mixed to make alloys
-many found together; difficult to separate

19. Alloy
Actinides
-mixture of two or more metals
-below lanthanides
-only actinium (Ac), thorium (Th), protactinium (Pa), and uranium (U) occur naturally
*U used for energy in nuclear power plants
-all elements heavier than U created in labs
*nuclei very unstable
*many only last a fraction of a second after made

20. Synthetic Elements
Particle Accelerators
-higher than #92
-synthesized when nuclear particles are forced to crash into each other
-move atomic nuclei faster and faster
-when crash, enough energy to make a single nucleus
-heavier than 95

21. Nonmetals and Metalloids

22. Nonmetal -lacks most properties of metals -poor conductors
-good insulators
-dull and brittle
-10 of 16 are gases at room temp
-bromine (Br) only liquid at room temp
-reactive with other elements; form compounds easily
-gain or share electrons
-fluorine (F) most reactive element

23. Carbon Family
-group 14
-gain, lose, share 4 electrons
-only carbon (C) is nonmetal
-C found in all living thing
-many fuels contain C: coal, gasoline

24. Boron Family
group 13
have 3 valence electrons
Boron (B) is the only metalloid, all other are metals
most common metal is aluminum (Al)

25. Nitrogen Family
Diatomic molecule
-group 15
-two nonmetals: nitrogen (N) and phosphorous (P)
-gain, share 3 electrons
-80% atmosphere is N gas (N2)
-consists of two atoms (N2, O2)

26. -P used to make matches (reacts with oxygen)
Nitrogen Family
-N is useful in fertilizer
-P more reactive than N
-P used to make matches (reacts with oxygen)

27. -group 16
-3 nonmetals: oxygen (O), sulfur (S), selenium (Se)
-gain, share 2 electrons
-O necessary for life (O2)
- is ozone (filters radiation from sun)
-O highly reactive (reacts with almost all other elements
-O most abundant element in crust
-S used to make rubber bands, tires
Oxygen Family

28. Halogen Family
-group 17
-fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At
-salt forming
-gains, shares 1 electron
-very reactive
-dangerous to humans uncombined
-useful when combined (F prevents tooth decay, Cl used in table and rock salt)

29. Noble Gases
-group 18
-un-reactive
-don’t gain or share electrons
-Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), Radon (Rn)
-exist in small amounts in atmosphere
-used in electric lights, (He) in balloons

30. Hydrogen -above group 1 -simplest, smallest element
-1 proton, 1 electron
-makes up 90% of atoms, but only 1% of mass of crust, oceans, atmosphere
-most in form of water (H2O)

31. Metalloids -characteristics of metals and nonmetals -zig za
-all solid at room temp
-brittle, hard, somewhat reactive
-most common silicon (Si)
-Si makes up sand, which makes glass
-most useful prop is varying ability to conduct electricity
*depends on temp, light, impurities

32. Semiconductors
-conduct electricity under some conditions, but not others
-used for computer chips, transistors, lasers