Atomic Theory
TrialEnergy per photon (eV)*Relative intensity of
lightElectrical current (mA)Max kinetic energy of e- if ejectedfrom
metal (eV)123456789 2.02.02.04.04.04.06.06.06.0
lowmediumhighlowmediumhighlowmediumhigh 000294360274055
0.00.00.00.90.90.92.92.92.9*eV = electron volts mA =
milliampsCatalyst 11/2/10 No New Objective Please have out chart to
be checked1. Which of the following statements best explains the
results of Trials13?A. The light was too intense to eject electrons
from the metal in the photocell.B. The light was too intense to
eject photons from the metal in the photocell.C.The energy per
electron was too high to eject photons from the metal in the
photocell.D. The energy per photon was too low to eject electrons
from the metal in the photocell.2. When 8.0 eV photons were shone
on the photocell, electrons ejected from the metal in the photocell
had a maximum kinetic energy of 4.9eV. Based on this information
and Table1, the relative intensity of the light shone on the
photocell:A.was high.B.was medium.C.was low.D.cannot be
determined.
AgendaSubatomic Particle Review (15-30)Ion and Isotope
Notes/Practice (30)Homework: 1, 2, 5 & 7: Pick 10 additional
elements to add to chart4 & 5 atoms, ions, and isotopes
worksheetName
1. 2.3....20.Symbol
atomic mass (A)
atomic number(Z)
protons(=Z)
neutrons(=A-Z)
electrons(=Z if neutral )
Homework:SymbolAtomic MassAtomic NumberHHydrogen11Protons:
1Neutrons: 0Electrons: 1NaSodium2311Protons: 11Neutrons:
12Electrons: 11RheniumRe18675Protons: 75Neutrons: 111Electrons:
75Try these:Name/ Atomic # Mass P N ESymbol
NiobiumInArsenicLeadAuZrVIronNiW
Atoms of the same element that differ in charge.(They have the
same # of p+, but different # of e-)ION Ex: How many electrons does
Sodium have?The atomic number equals the number of protons and the
number of electrons. 11 electronsNa1122.99Positive
Ions(cations)Negative Ions(anions) Na+ (lost 1 e-) Ca2+ (lost 2 e-)
Al3+ (lost 3 e-) Pb4+ (lost 4 e-) H+ (lost 1 e-)
Cl- (gain 1 e-) O2- (gain 2 e-) P3- (gain 3 e-) S2- (gain 2 e-)
OH- (gain 1 e-)
If an atom GAINS electrons, its overall charge becomes more
negative.If it LOSES electrons, its charge becomes more
positiveLearning Check CountingState the number of protons,
neutrons, and electrons in each of these ions. 39 K+ 16O -241Ca +2
198 20#p+ ___________________ #no ___________________#e-
___________________
Atoms of the same element that differ in mass.(They have the
same # of p+, but different # of N)ISOTOPE Isotopes are CHEMICALLY
the SAME as atoms, but DIFFER PHYSICALLY because they have
different masses. A few examples of isotopes
Learning Check Counting Naturally occurring carbon consists of
three isotopes, 12C, 13C, and 14C. State the number of protons,
neutrons, and electrons in each of these carbon atoms. 12C 13C14C 6
6 6#p+ _______ _______ _______ #no _______ _______ _______ #e-
_______ _______ _______
Answers12C 13C14C 6 6 6#p+ 6 6 6 #no 6 7 8 #e- 6 6 6
One Last Learning CheckWrite the nuclear symbol form for the
following atoms or ions:
A. 8 p+, 8 n, 8 e-___________
B.17p+, 20n, 17e-___________C. 47p+, 60 n, 46 e-___________
19So, why do the elements on the PT have masses with decimals???
The periodic table has the average atomic mass of all of the
isotopes of a substance
AVERAGE ATOMIC MASS Because of the existence of isotopes, the
mass of a collection of atoms has an average value.Boron is 20% 10B
and 80% 11B. That is, 11B is 80 percent abundant on earth. For
boron atomic weight = 0.20 (10 amu) + 0.80 (11 amu) = 10.8 amu
10B11BAverage atomic mass is calculated by: Mass each isotope
and multiply by amount Add calculations for each isotope Divide sum
by the total amount