EXAM 1 STUDY GUIDE Chapters 1-3, Study Guides, Projects, Research of Chemistry

Download EXAM 1 STUDY GUIDE Chapters 1-3 and more Study Guides, Projects, Research Chemistry in PDF only on Docsity! Chem 101 - Exam 1 - Study Guide Chapter 1 You should be able to: ● Identify the key steps in the Scientific Method. ➢ Step 1: Make observations. ➢ Step 2: Formulate a hypothesis. ➢ Step 3: Test the hypothesis through experimentation. ➢ Step 4: Accept or modify the hypothesis. ➢ Step 5: Develop into a law and/or a theory. ● Explain the dierence between an atom and an element. ➢ Atom: is the smallest component of an element, containing neutrons, protons and electrons, and makes up everything around us. ➢ Element: is a substance in which all of the atoms have the same atomic (proton) number. It is also defined as a substance which cannot be broken down by chemical means ● Describe the subatomic particles (protons, neutrons and electrons) and their location in the nuclear model of the atom. ➢ Electron: A negatively charged subatomic particle found outside the nucleus of all atoms. ➢ Neutrons: An electrically neutral with a mass & diameter slightly greater than that of a proton located in the nucleus ➢ Proton: A positively charged particle in the nucleus of an atom. ● Identify an element by its atomic number and chemical symbol ● Write the full atomic symbol for any neutral atom or ion. Chem 101 - Exam 1 - Study Guide ● Describe the organization of the periodic table by grouping elements containing shared properties. ➢ The periodic table is organized into groups (vertical columns), periods (horizontal rows), and families (groups of elements that are similar). ➢ Elements in the same group have the same number of valence electrons. ➢ Elements in the same period have the same number of occupied electron shells. ● Know the special names of following main groups in the periodic table: 1A, 2A, 6A, 7A, and 8A. ➢ Group 1A: Alkali Metals ➢ Group 2A: Alkaline Earth Metals ➢ Group 6A: Chalcogens ➢ Group 7A: Halogens ➢ Group 8A: Noble Gases ● Use the periodic table to identify the elements in metal, nonmetal and semimetal (metalloid) regions based on their location in the table. ➢ The metals are to the left of the line (except for hydrogen, which is a nonmetal), ➢ The nonmetals are to the right of the line ➢ The elements immediately adjacent to the line are the metalloids. ● Define isotopes and distinguish between atomic number and mass number. Chem 101 - Exam 1 - Study Guide ➢ All light travels at the same speed no matter its frequency, so light with a longer wavelength (distance between peaks) has a smaller frequency (since fewer waves pass by in one second) ➢ Light with a shorter wavelength has a larger frequency (more waves pass by per second). ➢ As wavelength increases, energy decreases ➢ As frequency increases, energy increases ● Describe the dierence between white light and atomic line spectrum, such as hydrogen emission. Chem 101 - Exam 1 - Study Guide ● Define the term line spectra. ➢ Emission spectra that are not continuous, but instead only discrete lines ➢ Line spectra are critical to our development of models of the atom ➢ Which emission spectrum is continuous? ; (H)-Hydrogen ● Describe the key features of the Bohr atom using the terms: orbits, quantum number, excited state and ground state. Chem 101 - Exam 1 - Study Guide ● Use the Bohr Model to identify electron transitions that emit visible light. Chem 101 - Exam 1 - Study Guide ● Describe the shape of s, p, and d orbitals. Chem 101 - Exam 1 - Study Guide Atomic Orbitals—p Orbitals ¢ Beginning with the second principal energy level (n = 2), in addition to the s sublevel, there is now a p sublevel present. ¢ Ap sublevel contains 3 p orbitals that are shaped like dumbbells. * Each of the p orbitals lies along one of the axes. + All p orbitals are perpendicular to one another. a (a) (b) (c) Atomic Orbitals—d and f Orbitals * Beginning with the third principal energy level (n = 3), there is also a d sublevel containing five d orbitals. * Beginning with the fourth principal energy level (n = 4), there is an f sublevel, which contains seven f orbitals. The shapes of the f orbitals are highly complex (not shown). 5 d orbitals 3dyy Chem 101 - Exam 1 - Study Guide ● Construct orbital diagrams and write electron configurations for elements and main group ions. ➢ https://www.youtube.com/watch?v=6dRdMy9tgzE Chem 101 - Exam 1 - Study Guide ● Describe and apply the periodic table trends for ➢ atomic size ➢ metallic character Chem 101 - Exam 1 - Study Guide ➢ ionization energy – the ability of an element to lose an electron Chem 101 - Exam 1 - Study Guide ➢ electron anity – the tendency for an element to gain an electron Chem 101 - Exam 1 - Study Guide lons: The Loss and Gain of Electrons— Drawing Lewis Dot Symbols of lons ¢ We can represent ions of main-group elements with Lewis dot symbols. * Write the Lewis dot symbol of an atom and then remove a dot for each electron it loses, or add a dot for each electron it gains. 3? atom Nae ‘CL : ion Nat and EC: Problem — Lewis Dot Structures — Atoms and lons * Write the Lewis dot symbols for (1) the atom and (2) the ion commonly formed by each element. Element |_MainGrp Valence | LewisDot| Valence Lewis Dot # e~ atom atom e- ion i ion P oe AeA 7 54 g e : elt) [: iP ‘| Sia Ga © | ies aap eee} chee Sr n ° O At ye el AA A Gre 2-222) Y ZL). Was ~ C79 FOE Ey rw 4 OW & 18 ‘ Chem 101 - Exam 1 - Study Guide Chapter 3 You should be able to: ● Classify matter as an element, compound or mixture. ➢ Matter:anything that has mass and occupies space ❖ There are all kinds of matter. (coee, cup, computer, birthday cake or even a candle) ➢ Element: simple kind of matter, slightly more than 100 exist ❖ Shiny/Lustrous ❖ Electrical Conductivity ➢ Compound: two or more elements that are chemically combined ➢ Mixture: combination of pure substances ❖ Each pure substance in a mixture can be physically separated ➢ Pure Substance: only one kind of matter; can be one element or one compound ❖ Cannot easily be broken down into other things (e.g Gold) ❖ Gold bars (at the atomic level) consist only of elemental gold ● Distinguish between heterogeneous and homogeneous mixtures. ➢ Heterogeneous: means having dierent kinds See dierences in appearance and composition ➢ Homogenous: means the same throughout (air, saline solution) ❖ Well-blended; appears the same throughout ❖ Solutions are homogeneous mixtures Is salt a pure substance? ➔ At the atomic level, the salt crystals consist only of the elements sodium and chlorine in a specific and constant pattern; Thus; salt is a pure substance Is Iced Tea a pure substance? ➔ Ice consists of one compound (water) in a solid state ➔ Tea consists of water (liquid) plus sugar, and compound extracted from the tea leaves ➔ The content is heterogeneous; however as a whole, iced tea is a homogeneous mixture (a solution) Chem 101 - Exam 1 - Study Guide ● Identify the phases of matter as solid, liquid or gas. ➢ Solids: definite shape and definite volume ➢ Liquid: definite volume, but they take on the shape of the container they occupy ➢ Gases: neither definite shape nor definite volume. Must be contained on all sides, taking on the shape and volume of the container ● Distinguish between chemical property, chemical change, physical property and physical change. ➢ Physical Property: Characteristics and appearances ❖ Uses your senses (Except never taste in lab) ❖ Displays without changing its composition ❖ Some physical properties are odor, color, taste, appearance, melting and boiling point, hardness, magnetism, density, thermal conductivity, electrical conductivity. ★ Strawberries: smells and tastes sweet, hard and red in color. ➢ Physical Change: A substance changed without losing its original identity ★ One Example: water is still water whether it is a solid, liquid, or gas. It is just a phase change ➢ Chemical Property: Properties a substance displays only by changing its composition due to a chemical change ○ Is the substance transformed into a new substance? ❖ When combined with other chemicals ❖ When exposed to heat or light ★ Examples are flammability, corrosiveness, reactivity with acids, toxicity (Gasoline is flammable) Chem 101 - Exam 1 - Study Guide ● Write the correct formula for a binary ionic compound containing a cation with a variable charge. ➢ Atomic Cation are named by adding the word ion to the name of the element ❖ For metals that form ions with more than one possible charge, the ion’s name must also include the charge ❖ Use roman numerals in parentheses immediately following the element’s name ➢ An atomic anion is named by changing the ending of the elemen’s name to -ide and adding the word ion. ➢ Because non-metals form anions with predictable charges, it is not necessary for the ion’s name to specify its charge Chem 101 - Exam 1 - Study Guide ➢ A type I binary ionic compound is named using the name of the cation followed by the name of the anion – eliminating the word on from each ➢ The nomenclature for type II binary ionic compounds is essentially the same as that of type I, except that the charge on the cation, in the form of a parenthetical Roman numeral, is part of the name Chem 101 - Exam 1 - Study Guide Sample Problem and Strategy * Determine the name of each of the ionic compounds: (a) CaN, casey nFrde ‘ (b) MgCl, 2gHesya ehlarde 4 (c) Cu,0 epee ® wide 2Cu* YA (d)Zncl, 22 chlorae (e) Min,O; WAM GAMELE Eide (f) Lise , Liam plesplyne * Strategy * The name of an ionic compound is (1) the name of the cation (positive ion) then name the anion (negative ion). * Only metals that form more than one ion should include a Roman numeral as part of their name.