1. CATEGORIZE ELEMENTS AS METALS, NONMETALS, METALLOIDS AND NOBLE GASES.
RECOGNIZE PERIODIC TRENDS OF ELEMENTS, INLCUDING THE NUMBER OF VALENCE ELECTRONS, ATOMIC SIZE AND REACTIVITY.
CATEGORIZE ELEMENTS AS METALS, NONMETALS, METALLOIDS AND NOBLE GASES.
DIFFERENTIATE BETWEEN FAMILIES AND PERIODS.
USE ATOMIC NUMBER AND MASS NUMBER AND MASS NUMBER TO IDENTIFY ISOTOPES.
COS 1.0, 1.1, 1.2, 1.3

2. WHAT YOU’LL LEARN
State the charge, mass, & location of each part of an atom according to the modern model of the atom.
Relate the organization of the periodic table to the arrangement of electrons within an atom.
Identify isotopes of common elements.
Determine how many protons, neutrons, & electrons an atom has, given its symbol, atomic number, & mass number.
Locate alkali metals, alkaline earth metals, & transition metals in the periodic table.
Locate semiconductors, halogens, & noble gases in the periodic table.

3. ATOMIC STRUCTURE

4. WHAT ARE ATOMS?
smallest part of an element that still has element’s properties.
building blocks of molecules

5. WHAT’S IN AN ATOM?

6. NUCLEUS
center of each atom
small & dense
has positive electric charge

7. PROTONS
subatomic particle that has positive charge
found in nucleus

8. NEUTRONS subatomic particle that has no charge no overall charge
equal number of protons and electrons whose charges exactly cancel

9. ELECTRONS subatomic particles with negative charges.
located in a cloud (orbit) moving around outside nucleus

10. QUARKS
particles of matter that make up protons and neutrons

11. MODELS OF THE ATOM

12. DEMOCRITUS Greek philosopher developed theory around 400 B.C.
proposed that atoms make up all substances
Atom — “unable to be divided”

13. JOHN DALTON Developed atomic theory in 1808
first atomic theory with a scientific basis
model was simple sphere
thought the atom could not be split
Atoms of same element exactly alike

14. NIELS BOHR theory developed in 1913
suggested that electrons in an atom move in set paths around the nucleus much like planets orbit sun
It is impossible to determine an electrons:
exact location
speed
direction
Best scientists can do is:
calculate chance of finding an electron in a certain place within an atom

15. J.J. Thomson (1897) Discovered negatively charged particles
atom was divisible!
Particles discovered are electrons
Atom consists of positively charged material with negative charges spread evenly throughout

16. Rutherford (1908) Gold Foil Experiment
Positive particles shot at gold foil occasionally bounced back!
Proposed dense, positively charged center called the nucleus

17. ENERGY LEVELS
path of a given electron's orbit around a nucleus, marked by a constant distance from the nucleus
Closer to nucleus, lower energy level of electrons
Further from nucleus, more energy electrons have
Number of filled energy levels an atom has depends on number of electrons

18. ORBITAL
region in an atom where there is a high probability of finding electrons

19. VALENCE ELECTRONS found in outermost shell of an atom
determines atom’s chemical properties
participate in chemical bonding
Every atom has between one and eight

20. THE PERIODIC TABLE

21. ORGANIZATION OF THE PERIODIC TABLE
Groups similar elements together
organization makes it easier to predict properties of an element based on where it is in periodic table
Elements are listed in order of number of protons

22. PERIODIC LAW
states that when elements are arranged this way, similarities in their properties will occur in a regular pattern
helps determine electron arrangement

23. PERIODS Horizontal rows
number of protons & electrons increases as you move from left to right

24. FAMILY/GROUP vertical column of elements
Atoms of elements in same group have same number of valence electrons
elements have similar properties

25. IONS
an atom or group of atoms that has lost or gained one electron and has a negative or positive charge

26. HOW THE STRUCTURES OF ATOMS DIFFER

27. ATOMIC NUMBER (Z)
number of protons in the nucleus

28. MASS NUMBER (A)
number of protons plus the number of neutrons in nucleus

29. ATOMIC RADIUS is size of atom GROUPS
radius increases as one proceeds down any group of periodic table
WHY?
adding layers of electrons
PERIODS
radius decreases as one proceeds across any row of periodic table
increasing number of protons in nucleus as you go across the period pulls electrons in more tightly.

30. ISOTOPE
has same number of protons as other atoms of same element do but has a different number of neutrons.
Some are more common than others.
If you know the atomic number and mass number of an atom, you can calculate the number of neutrons it has.

31. Example
Chlorine 35 has a mass number of 35. Has an atomic number of 17.
Mass number (A): 35
Atomic number (Z): –17
Number of neutrons: 18

32. ATOMIC MASS UNIT (amu)
Mass of an atom or molecule that is exactly 1/12th the mass of a carbon atom with mass number 12

33. AVERAGE ATOMIC MASS
weighted average of masses of all naturally-occurring isotopes of an element

34. AVERAGE ATOMIC MASS EXAMPLE
About 8 out of 10 chlorine atoms are chlorine-35. Two out of 10 are chlorine-37.
Avg.
Atomic
Mass
35.4 u

35. FAMILIES OF ELEMENTS

36. HOW ARE ELEMENTS CLASSIFIED?
By similar physical & chemical properties.

37. ALKALI METALS group 1 shiny malleable ductile React violently w/ water
Very reactive b/c it has only one valence electron
Has +1 charge
Not found in nature as elements
Found only in compounds
Ex: salt (NaCl)
Lithium
used to treat bipolar disorder

38. ALKALI EARTH METALS Group 2 two valence electrons +2 charge shiny
malleable
ductile
Form compounds in stone & human body
Calcium (Ca):
Shells of sea animals, coral reefs (limestone), skeletal structure humans …
Magnesium (Mg)
Air plane construction
Activates enzymes that speed up processes in humans
brilliant white color in fireworks
Medicines
milk of magnesia
Epsom salt

39. TRANSITION METALS groups 3-12 most familiar found in elemental state
Iron
most abundant metal
used in steel
Aluminum
making containers, automotive parts, cookware…
MERCURY
only metal at room temperature
used in thermostats, thermometers, batteries …

40. NONMETALS
Some elements found in groups & all elements in groups 17-18
except hydrogen
usually gases or brittle solids at room temperature
poor conductor of heat & electricity
may be solids, liquids, or gases at room temperature.

41. HALOGENS Group 17 very reactive in elemental state Chlorine
greenish yellow gas
Kills bacteria
Elemental chlorine is very poisonous
obtained from seawater
Fluorine
Poisonous yellow gas
used in toothpaste
Bromine
Dark red liquid
only nonmetal liquid at room temperature
Iodine
shiny, purple-gray solid
Used as disinfectant

42. NOBLE GASES group 18 Exist only as single atoms instead of molecules
Unreactive b/c orbitals are full of electrons
Neon
Signs
Helium
Less dense than air
Gives lift to blimps & balloons
Argon/Krypton
Used in light bulbs

43. SEMICONDUCTORS
elements that can conduct electricity under certain conditions
Aka metalloids:
Composed of only six elements
Boron, silicon, germanium, arsenic, antimony & tellurium
Boron
Extremely hard
Added to steel to increase hardness & strength at high temperatures.
Antimony
Used as fire retardants
Silicon
Makes up 28% of earths crust
Sand most common compound
Used in electronics