2. (almost 2,000)

3. • # of
protons in
atom’s
nucleus
•used to
identify Atomic mass number
element
•sum of protons & neutrons

4. isotope-
element
with same #
of protons &
different #
of neutrons

5. Pre-Periodic Table Chemistry …
• …was a mess!!!
• No organization of elements.
• Imagine going to a grocery
store with no organization!!
• Difficult to find information.
• Chemistry didn’t make sense.

6. Dmitri Mendeleev: Father of the Table
HOW HIS WORKED… SOME PROBLEMS…
• Put elements in rows • He left blank spaces
by increasing atomic for what he said were
undiscovered
mass. elements. (Turned
• Put elements in out he was right!)
columns by the way • He broke the pattern
they reacted. of increasing atomic
weight to keep similar
reacting elements
together.

7. Each square of periodic table
includes:
– element’s atomic number= #
of protons in its nucleus
– chemical symbol
– name
– atomic mass= avg. mass of all
isotopes of that element
15.9994

8. Chemical symbol
• 1 or 2 letters
• ex: iron= Fe

9. Periods
• Horizontal rows
• 7 periods

10. Groups
• columns
• aka families
• 18 groups
• eg: Group 15= nitrogen family
• each group has similar characteristics

11. physical properties of a metal
• hardness
• shininess
• malleable=can be pounded into shapes
• ductile=can be pulled out into a long wire
• conductor - can transmit heat & electricity
• magnetic
• most are solids at room temp.
(except ___________ )
mercury

12. chemical properties of a metal
reactivity
• __________= ease & speed at which an
element combines or reacts with other
elements
• some - very reactive (ie. sodium)
• others - unreactive (ie. gold)

13. • reactivity ease & speed at which an
__________=
element combines or reacts with other
elements
• some - very reactive (ie. sodium)

14. corrosion
• process of reaction &
wearing away
• ie. iron rusting

15. alloy
• mixture of metals
• ie. copper + tin= bronze

16. Group 1- alkali metals
– from Li  Fr (not H)
– very, very reactive
Potassium reacting with water
– have 1 valence electron
Lithium reacting with water

17. Group 2- alkaline earth metals
• 2nd column
• Be  Ra
• very reactive- never alone
• lose 2 valence electrons
• most common- Ca & Mg

18. Groups 3-12 - transition metals
• bridge between very reactive metals &
less reactive metals
– ex: Fe, Ag, Pt

19. Groups 13-16
– incl metals, nonmetals &
metalloids
– ex. Al, Sn, Pb

20. lanthanides & actinides-
rare earth elements
• found @ bottom of periodic table
• fit in periods 6 & 7
• placed at bottom for convenience

21. Neodymium, one of the lanthanide elements, is
used in manufacturing the tiny speakers inside
stereo headphones.

22. Curium, one of the actinide elements,
is used as a source of high-energy particles that heat
and provide power for certain scientific equipment
aboard the Mars Exploration Rover.

23. synthetic elements
• elements w/ atomic # > 92
• not found naturally on Earth
• made when nuclear particles collide

24. particle accelerators
• make elements above atomic #95
• move atomic nuclei until reach very high
speeds

25. • Element 110-118, elements with
three-letter symbols, have been
given temporary names and symbols.
• In the future, scientists around the
world will agree on permanent
names and symbols for these
elements.

26. Nonmetal
• Element that lacks most
properties of metals
–dull- not shiny
–brittle- not malleable
–poor conductors

27. Nonmetals
• Located at right of zigzag line on
periodic table
• 10/16 = gases
• Most form compounds, except
Group 18

28. Boron Family
• Group 13

29. Carbon Family
• Group 14
• C (nonmetal)  Pb
• 4 valence electrons

30. Carbon Family
• Contains elements
important to life &
computers
• Carbon = basis for entire
branch of chemistry
• silicon & germanium-
important semiconductors

31. Nitrogen Family
• Group 15
• N  Bi
• 2 nonmetals- N & P
• 5 valence electrons

32. • Group 15
Nitrogen Family • Nitrogen makes up over
¾ of the atmosphere.
• Nitrogen and
phosphorus are both
important in living
things.
• Most of the world’s
nitrogen is not available
to living things.
• The red stuff on the tip
of matches is
phosphorus.

33. Oxygen Family
• Group 16
• O Po
• 3 nonmetals- O, S, Se
• 6 valence electrons

34. Diatomic molecules
• Compounds of 2 identical
atoms

35. Halogen Family
• Group 17
• F  At
• 7 valence electrons
• very reactive
• typically gains or shares 1
electron

36. Halogens
• Group 17
• Very reactive, volatile,
diatomic, nonmetals
• Always found
combined with other
element in nature
• Used as disinfectants
& to strengthen teeth

37. Noble Gases
• group 18
• He  Rn
• 8 valence electrons
• very stable & unreactive
• do not form compounds b/c do not gain,
lose, or share valence electrons

38. The Noble Gases
• Group 18
• VERY unreactive,
monatomic gases
• Used in lighted “neon”
signs
• Have a full valence
shell.

39. Hydrogen
• alone in upper corner
• not grouped in a family
• very diff. properties
• has 1 proton & 1 electron
• some have neutrons

40. Metalloids
• on border
between metals &
nonmetals
• 8 metalloids
• characteristics of
both metals &
nonmetals

41. Metalloids
• most useful property= varying
ability to conduct electricity
–used to make semiconductors=
can conduct electricity under
certain conditions

42. Review
1. What can you predict from an element’s location
in the periodic table?
2. To make most synthetic elements, scientists use
powerful machines called ___________.
3. Which group contains the most elements?
4. What prediction did Mendeleev make that came
true less than 20 years later?
5. Fluorine, chlorine, bromine, and iodine are part of
what family?

43. Bo