Catalyst 11/2/10 No New Objective Please have out chart to be checked 1. Which of the following statements best explains the results of Trials 1–3 ? 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 4.9 eV. Based on this information and Table 1, the relative intensity of the light shone on the photocell: A.was high.B.was medium.C.was low.D.cannot be determined.

Agenda Subatomic Particle Review (15-30) Ion and Isotope Notes/Practice (30) Homework: –1, 2, 5 & 7: Pick 10 additional elements to add to chart –4 & 5 atoms, ions, and isotopes worksheet

Name Symbolatomic mass (A) atomic number (Z) protons (=Z) neutrons (=A-Z) electrons (=Z if neutral ) Homework:

Symbol Atomic Mass Atomic Number

H Hydrogen 1 1 Protons: 1 Neutrons: 0 Electrons: 1

Na Sodium Protons: 11 Neutrons: 12 Electrons: 11

Rhenium Re Protons: 75 Neutrons: 111 Electrons: 75

Try these:Name/ Atomic # Mass P N E Symbol Niobium In Arsenic Lead Au Zr V Iron Ni W

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 electrons Na

Positive Ions (cations) Negative Ions (anions) Na + (lost 1 e - ) Ca 2+ (lost 2 e - ) Al 3+ (lost 3 e - ) Pb 4+ (lost 4 e - ) H + (lost 1 e - ) Cl - (gain 1 e - ) O 2- (gain 2 e - ) P 3- (gain 3 e - ) S 2- (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 positive

Learning Check – Counting State the number of protons, neutrons, and electrons in each of these ions. 39 K + 16 O -241 Ca #p + ___________________ #n o ___________________ #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, 12 C, 13 C, and 14 C. State the number of protons, neutrons, and electrons in each of these carbon atoms. 12 C 13 C 14 C #p + _______ _______ _______ #n o _______ _______ _______ #e - _______ _______ _______

Answers 12 C 13 C 14 C #p #n o #e

One Last Learning Check Write 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 - ___________

So, 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.Because of the existence of isotopes, the mass of a collection of atoms has an average value. Boron is 20% 10 B and 80% 11 B. That is, 11 B is 80 percent abundant on earth.Boron is 20% 10 B and 80% 11 B. That is, 11 B is 80 percent abundant on earth. For boron atomic weightFor boron atomic weight = 0.20 (10 amu) (11 amu) = 10.8 amu = 0.20 (10 amu) (11 amu) = 10.8 amu 10 B 11 B

Average atomic mass is calculated by: 1. Mass each isotope and multiply by amount 2. Add calculations for each isotope 3. Divide sum by the total amount