Unit 1: The Atom The following pages are practice questions for this unit, and will be submitted for homework! You must complete: Unit Vocabulary ALL QUESTIONS What is an Atom? ALL QUESTIONS Calculating the Number of Protons, Neutrons, and Electrons ALL QUESTIONS Calculating Average Atomic Mass ALL QUESTIONS History of the Atom ALL QUESTIONS Excited Electron Cartoon Analysis ALL QUESTIONS Atomic Spectra Practice ALL QUESTIONS Ground State vs. Excited State ALL QUESTIONS Bohr Diagrams foe Excited and Ground State ALL QUESTIONS DUE: Thursday October 11, 2018 1
Unit Vocabulary Atom: Atomic Mass: Atomic Number: Bohr: Bright Line Spectra: Electron Configuration: Electron: Excited State: Gold Foil Experiment: Ground State: Isotope: Neutron: Nuclear Charge: Nucleus: Orbital: Proton: Rutherford: Thompson: Valence Electrons: Wave Mechanical Mode: 2
What s in an Atom? Directions: Use your knowledge of chemistry to fill in the table below. Subatomic Particle Location Charge Relative Mass Proton Neutron Electron Directions: Label the parts of an atom. Write your answer on the arrow. Calculating the Number of Protons, Neutrons, and Electrons Directions: Using your reference table and your knowledge of chemistry, fill in the following chart. Element Name Symbol Atomic Number Atomic Mass Mass Number # of Protons # of Electrons # of Neutrons Silver C Zn 5 25 Kr 35.45 3
Calculating Average Atomic Mass Directions: Using your reference table and your knowledge of chemistry, calculate the average atomic mass. 1. Chlorine has 2 naturally occurring isotopes. Using the information provided below, calculate the average atomic mass for chlorine. SHOW ALL WORK. Isotope Natural Abundance on Earth (%) Atomic Mass (amu) 35 Cl 75.77 34.968852 37 Cl 24.23 36.965903 2. Titanium has 5 naturally occurring isotopes. Using the information provided below, calculate the average atomic mass for titanium. SHOW ALL WORK. Isotope Natural Abundance on Earth (%) Atomic Mass (amu) Ti-46 7.93 45.95263 Ti-47 7.28 46.9518 Ti-48 73.94 47.94795 Ti-49 5.51 48.94787 Ti-50 5.34 49.9448 3. Natural samples of copper contain two isotopes. 63 Cu has a mass of 62.930 amu and 65 Cu has a mass of 64.928 amu. The percent abundance of 63 Cu is 69.09%. Calculate the average atomic mass of copper. 4
4. Calculate the atomic mass of an element if 60.4% of the atoms have a mass of 68.9257 amu and the rest have a mass of 70.9249 amu. Identify the element in the periodic table. History of The Atom Directions: Using your knowledge of chemistry, fill in the chart below. Scientist Major Discovery Drawing of Atom John Dalton JJ Thompson Ernest Rutherford Niels Bohr Erwin Schrödinger 5
Excited Electron Cartoon Analysis Directions: Using your knowledge of chemistry, describe what is happening in each of the four images. Each description needs AT LEAST 2 COMPLETE SENTENCES! 6
Atomic Spectra Practice Directions: Look at the following images, and answer the questions that follow. Image A: 1. What elements are in the mixture? Explain! 2. What elements are NOT in the mixture? Explain! 3. Describe in terms of both electrons and energy states, how the light represented by the spectral lines is produced. Image B: 4. What elements are in the mixture? Explain! 5. What elements are NOT in the mixture? Explain! 6. Describe in terms of both electrons and energy states, how the light represented by the spectral lines is produced. 7
Ground State vs. Excited State Directions: Looking at the electron configurations, determine the element, and whether or not the element is shown in the ground or excited state. The first one has been done for you as a model. Starter Question: Does exciting electron change the number of electrons? YES or NO Starter Question: If neutral, the number of electrons is equal to the. 1. ELECTRON CONFIGURATION: 2-4 The electron configuration 2-4 represents the element CARBON because 2+4 = 6. There are 6 electrons represented. Since the atom is neutral the number electrons equals the number of protons, so this element has 6 protons which can ONLY be carbon, because the number of protons is the same as the atomic number which is unique for each element. It is in the GROUND STATE because there are no additional shells represented before a previous one has been filled to capacity. 2. ELECTRON CONFIGURATION: 2-5-1 3. ELECTRON CONFIGURATION: 2-7-1 4. ELECTRON CONFIGURATION: 2-8-2 5. ELECTRON CONFIGURATION: 2-8-2-1 8
Bohr Diagrams for Excited and Ground State Directions: Draw the Bohr diagrams of the elements discussed in the chart above Element Name/Symbol Electron Configuration Excited or Ground State? EXPLAIN Bohr Diagram 2-5 2-8-5-1 2-8-7-3 2-8-7-2 9