CHEM 1465 1st Edition Lecture 2Chapter 1 – Introduction to Chemistry (continued)Metrix PrefixesGiga (G) 109Mega (M) 106Kilo (k) 103Deci (d) 10-1Centi (c) 10-2Mili (m) 10-3Micro (µ) 10-6Nano (n) 10-9Pico (P) 10-12Femto (f) 10-15Temperature - The SI unit is Kelvin (Kelvin is on an absolute scale- meaning no negative numbers)- K = ºC + 275.15- ºC = (ºF-32) / 1.8- ºF = (1.8 × ºC) + 32Significant Figures Rules for determining which digits are significant 1) All non-zero digits are significant (5.32 has 3 sig. figs.)These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.2) A zero between 2 significant figures is significant (5.002 has 4 sig. figs.)3) Leading zeros are not significant (0.00532 has 3 sig. figs.) 4) Final zeros in a number with a decimal point are significant (15.0 and 150. both have 3 sig. figs.)5) Final zeros without a decimal point are ambiguous (150 could have 2 OR 3 sig. figs.)Significant figures in Calculations Rule 1 – Multiplication and division - The question is “how many sig figs?” Use the number of sig figs that is least. - 2.99 x 7.3 = [21.827] - The final answer is 22Rule 2 – Addition and subtraction - The question is “how precise?” Carry out the answer to the least precise sig fig.- 29.52 + 3.001 + 7219.5 = [7252.021]- The final answer is 7252.0Exact numbers: do not limit the number of significant figures1.) Counted objects (20 students, 3 cats)2.) Some conversion factors are exact by definition (2.54 cm = 1 in)Chapter 2 – Atoms and Molecules Atomic Structure and Mass Subatomic Particle Abbreviation Mass (kg) Mass (amu) Charge Proton P, H+1.67262x10-27~ 1+1.609x10-19(+1)Neutron N 1.67492x10-27~ 1 0Electron e-9.109x10-31~ 1/200th-1.609x10-191.)Atom: Always neutral because number of protons is equal to number of electrons2.) Ion: a charged particle, atom, element, or molecule (number of protons DOES NOT equal number of electrons)3.)Cation: a positively charged ion 4.)Anion: a negatively charged ion5.)Atomic number: equal to the number of protons and defines the element (symbolized by Z)6.)Mass number: equal to the number of protons plus neutrons (symbolized by A)7.)Isotopes: atoms of same element that differ only by number of neutrons Examples:12C13C14C23Na+ 31P3-Protons 6 6 6 11 15Neutrons 6 7 8 12 16Electrons 6 6 6 10 18Atomic Masses: weighted average of the natural occurring isotopes. Referred to as atomic weight, averageatomic mass, and also molar massExample: Isotope mass (amu) abundance 24Mg 23.9850 78.99% 25Mg 24.9858 10.00%26Mg 25.9826 11.01%Compounds and Chemical Bonds - Chemical compound: 2 or more elements held together by chemical forces- Chemical Formula: shows the number and types of atoms1. Molecular formula: exact number of elements (C3H6)2. Empirical formula: relative number of each element (CH2)- Chemical Bonds: involve the exchange or sharing of electrons. Elements do this to become more stable.- Three types1. Ionic: metals lose an electron to become a cation and nonmetals gain an electron to become anion2. Metallic: sea of electrons with delocalized sharing (occurs with metals)3. Covalent: typically between 2 nonmetals sharing electronsThe Periodic Table: elements grouped in given vertical column share similar chemical and physical