Chemistry

Periodic The Table 1 Lavoisier Made the first list of 30 substances he thought were elements D?bereiner Created a list of elements based on triads triads: groups of 3 elements with similar properties Created a list of elements based on triads problem with triads: Soon more elements were found; there were more than 3 similar elements to a group. D?bereiner periodicity repetition of a property on a regular basis Newlands Arranged elements by atomic mass Observed the ?law of octaves? Every 8th element repeats properties. Included the transition metals Mendeleev Developed the periodic table by arranging elements by atomic mass (like Newlands) Included the transition metals (like Newlands) Mendeleev Left blanks when properties or mass did not fit

The Electron Structure of the Atom The quantum model emphasizes the wave nature of electrons. The Quantum Model Quantum numbers are solutions to the wave equations of electrons. Scientists use a set of 4 quantum numbers to determine an electron?s location around an atom. Quantum Numbers Electrons exist in principal energy levels that correspond to Bohr?s orbits: 1, 2, 3, 4, 5, ? Principal energy levels are divided into 4 types of sublevels: s, p, d, and f. Where are the Electrons? The sublevels contain orbitals. Each orbital can hold up to two electrons. Where are the Electrons? Identifies the principal energy level Correlates to Bohr?s orbits n = 1, 2, 3, 4, 5, 6, or 7 for the ground state e?. The total number of e? in a level is 2n2. Principal Quantum Number (n) Level Total # e? 1

Measurements Mathematics and 1 Calculations with Sig Digs Rules for Adding and Subtracting Measured data must be the same kind of dimension and have the same units before they can be added or subtracted. The sum or difference of measured data cannot have greater precision than the least precise quantity in the sum or difference. Rules for Adding and Subtracting = 23.8 cm 23.80 cm 2.1 cm 21.70 cm + 262,729.12 = 263,000 259,000 3,729 0.12 + Rules for Multiplication and Division The product or quotient of measured data cannot have more SDs than the quantity with the fewest SDs. The product or quotient of a measurement and a counted number, conversion factor, or defined value has the same number of decimal places, or the same precision, as the original measurement.

Measuring and Units 1 All slides in this section contain: Clipart.com items: 8260752, 7804277 The Dominion Mandate requires us to gain knowledge about God?s creation. To do so, we must take measurements. Measurement measurement the act of comparing an unknown quantity to a standard unit When you write a measurement ? You must have a number. You must have a unit. (How much information does the statement ?I ran 7? give you?) instrument a device to aid in measuring Is accurately subdivided Is calibrated Instrument Has units on a scale Started with the metric system. Expanded to SI. SI System (International System of Units) We will use 5 of these. There are 7 base units. SI System (International System of Units) base units units that do not come from other units Chemistry Base Units

Energy and Matter Energy Energy the ability to do work Work Work a force moving matter through a distance Both energy and work are measured in joules (J). Forms of Energy Mechanical ? objects Kinetic ? moving Potential ? stored Thermal ? kinetic energy of atoms and molecules Forms of Energy Acoustic (sound) ? periodic, wave-like motion of atoms and molecules Electromagnetic ? moving electrons Chemical ? breaking and forming bonds Forms of Energy Nuclear ? from center of atom 6 Energy Conservation Despite Change ?the study of the flow of energy? Thermodynamics ?the law of conservation of mass-energy? (Conservation doesn?t refer to turning off the lights.) First Law of Thermodynamics ?the law of conservation of mass-energy?