the atom & the periodic table jen rosenthal. review of the atom fill in the following table...
TRANSCRIPT
The Atom & the Periodic Table
Jen Rosenthal
Review of the AtomFill in the following table based on what you learned from last class about the
atom.
Subatomic Particle
Location within the atom
Charge Mass
neutron In the nucleus 0 or neutral 1 amu
proton In the nucleus +1 1 amu
electron Outside of the nucleus
-1 0 amu
History of the Periodic TableDmitri Mendeleev
• Searched for way to organize elements• Put them in order of increasing masses
How do you read the periodic table?
Parts of the Periodic Table
What you need to know
http://www.classzone.com/books/earth_science/terc/content/investigations/es0501/es0501page06.cfm
Key Terms to UnderstandTerm Definition Example
Atomic Number Equal to the # of protons in the nucleus and the # electrons in the electron cloud
Carbon (6) has 6 protons and 6 electrons
Atomic Mass Average mass of all of the element’s isotopes
Carbon (12.01) amu which is unified atomic mass units
Mass Number/Atomic weight
The sum of the protons + the neutrons (# of protons + # of neutrons)
Carbon (12.01), where 12.01 amu represents the sum of protons (6) + neutrons (6)
Isotope Two nuclides (a particular kind of nucleus) that have the same atomic number but a different mass number
24Mg (79% of all Mg atoms), 25Mg (10%), and26Mg (11%); all three are isotopes of Mg (atomic # =12) and are present in all compounds of magnesium in about these same proportions.
Atomic Calculations# of electrons = atomic numberEx: Magnesium (Mg) has _12__ electrons
# of protons = atomic numberEx: Sodium (Na) has _11_ protons
# of neutrons = mass number (atomic mass rounded to nearest whole number) – atomic number
Ex: Tin (Sn) has _69____ neutrons
Atomic Weight, Molecular Weight, & Formula Weight
Atomic Weight- comes from the Periodic Table & is a measure of the average mass of the isotopes of the element
Molecular Weight- is the mass of a molecular compound (water)Ex: H20 = 2 Hydrogen atoms = 2 x 1.01 = 2.02
1 Oxygen atom = 1 x 15.99= 15.99Molecular Weight of water = 18.01 amu
Formula Weight- is the mass of an ionic compound (salt)Ex: NaCl = 1 sodium atom = 22.99 1 chlorine atom = 35.45Formula weight of salt = 58.44 amu
Understanding the Periodic Table
Orbitals (n =2) two electrons can fit inside of one orbital
Sublevels (s,p,d,f)Where s = 1, p = 3, d = 5, f = 7
Energy LevelsRelates directly to # of
horizontal periods in the Periodic Table (1 to 7)
Atomic Apartment BuildingThink of the apartments as only being able to hold two people per room & has 7 floors. Apartment Type # of rooms # of people s 1 2 p 3 6 d 5 10 f 7 14
7
6
5
4
3
2
1 1s
1s2s2p
3s3p
4s3d 4p
5s4d
5p
6s
5d 6p
7s
6d
SublevelsElectron orbital designated as s,p,d,&f
More Terms to understand bondingTerm Definition Example
Cation Positively charged ion Na+1
Anion Negatively charged ion Cl-1
Valence Electrons Electrons in the outermost energy level that can be involved with chemical changes and bonding
Next page
Activity 1: Understanding Periodic Trends
Instructions: Working in groups look at the following charts which show periodic trends for:
1. Atomic radii (atomic size)2. Ionization energy (the measure of energy required to
remove electrons from an atom)3. Electron Affinity (the measure of attraction between
incoming electrons from other atoms and the nucleus of original atom)
Describe what you notice about the charts and what you think they mean.
Write your thoughts in your science journal.
Atomic Radii
Atomic Radii Graph
Ionization Energy
Electron Affinity
Activity # 2 What’s in my cereal?
Materials: Special K cereal & cream of wheat, magnetic stir bar, hot plate, 750 to 1000 mL beaker
Procedure:1. Crush 50 g of Special K flakes with a mortar & pestle2. Fill beaker with 500 mL of water3. Place beaker on hot plate and add a magnetic stir bar, start the
stir function4. Add the crushed flakes to the water and wait 15 minutes5. Remove the magnetic stir bar6. Record your observations in your science journal.7. What do you think is on the stir bar? Check the cereal label to
think about which element you could have extracted from the cereal and explain why you think so.