LEWIS DOT STRUCTURES. (has 6 valence electrons, so needs 6 dots) (has 1 valence electron, so needs 1 dot) (has 7 valence electrons, so needs 7 dots)

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1 LEWIS DOT STRUCTURES The lewis dot structure for an element or compound should have the element surrounded by dots to represent VALENCE ELECTRONS. One dot should be placed on each side BEFORE doubling the dots up. O (has 6 valence electrons, so needs 6 dots) Na (has 1 valence electron, so needs 1 dot) Br (has 7 valence electrons, so needs 7 dots)

2 Lewis Dot in Ionic Compounds When given name of ionic compounds, first write the formula. Now you know how many of each element to draw. The before should have all elements and their lewis dot structures. The after should show the transfer of electrons with the new charges for the elements. Example: Magnesium Chloride Mg +2 Cl - 1 MgCl2 Mg + Cl + Cl à Mg +2 + Cl Cl charge is due to the LOSS of 2 electrons - 1 charge is due to the GAIN of 1 electron

Atomic Trends Atomic Radius (size)- the distance between nucleus and outer ring Ionization Energy- the amount of energy needed to remove a valence electron Electronegativity- the attraction between

3 Atomic Trends Atomic Radius (size)- the distance between nucleus and outer ring Ionization Energy- the amount of energy needed to remove a valence electron Electronegativity- the attraction between the positive nucleus and negative shared electrons Electron Affinity- the attraction between the positive nucleus and negative free- floating electrons ** Noble gases are NOT including in the electronegativity and electron affinity trends** 3 of the 4 trends increase as you move up and to the right on the periodic table Ionization Energy Electronegativity Electron Affinity 1 of the 4 trends increase as you move down and to the left on the periodic table Atomic Radius

4 Light and Electrons When electrons are excited with energy the have the ability to jump up to higher energy level (rings). As the drop back down to their original place, they emit a photon (particle of light). The photons that are released travel in waves. We use mathematical formulas to help us calculate wavelength, frequency, and the energy of light. c=λf c=speed of light= 3.0X10 8 (m/s) λ=wavelength (m) f=frequency (Hz) E=hf E=energy (J) h=plank s constant= 6.63x10-34 (J/Hz) f=frequency (Hz) E=hc/λ E=energy (J) h=plank s constant= 6.63x10-34 (J/Hz) c=speed of light= 3.0X10 8 (m/s) λ=wavelength (m) ß Photon of light

5 THE ELECTROMAGNETIC SPECTRUM The electromagnetic spectrum is the ran ge for all forms of light. This end of the EM Spectrum LOW energy LOW frequency LARGE wavelength This end of the EM Spectrum HIGH energy HIGH frequency SMALL wavelength Red Martians Invade Venus Using X- ray Guns

6 Ionic Compound Naming 1) Write the name of your cation (metal) 2) Write the name of your anion (non- metal) changing the ending to IDE. 3) If your cation is a transition metal, you must add roman numerals after to specify which charge the transition metals has 4) If your anion (or sometimes cation) is more than 1 element, look at the POLYATOMIC ION list to find its name Examples CaCl2 Calcium Chloride NaClO2 Sodium Chlorite Pb3(PO4)4 Lead (IV) Phosphate ß To figure out lead s charge and in turn its roman numeral, you had to UNSWAP and UNDROP the subscript numbers

7 Ionic Compound Formulas 1) Write the symbol and charge of your cation (metal) 2) Write the symbol and charge of your anion (non- metal) 3) If your cation is a transition metal, its charge will be the roman numeral number in parentheses 4) If your anion name ends in ate or ite, look at the POLYATOMIC ION list to find its symbols and charge 5) SWAP and DROP the numbers associated with the charges. Do not swap and drop the + or associated with the charge 6) Reduce the subscripts if you can Examples Lithium Sulfate Iron (II) Fluoride Aluminum Phosphate Li + SO4 2- Fe 2+ F - Al 3+ PO4 3- Li2SO4 FeF2 Al3(PO4)3 ß REDUCE AlPO4

8 ELECTRON CONFIGURATION Electron configuration is a written out address for where an atom s electrons are located. The periodic table is made up of 4 main orbitals (blocks) where electrons can be found. They are S, P, D, F. The S orbital can hold a maximum of 2 electrons. The P orbital can hold a maximum of 6 electrons. The D orbital can hold a maximum of 10 electrons. The F orbital can hold a maximum of 14 electrons. Within each orbital there are suborbitals that better pin point locations of electrons. Each suborbital can hold a max of 2 electrons. Therefore The S orbital contains 1 suborbital. The P orbital contains 3 suborbitals. The D orbital contains 5 suborbitals. The F orbital contains 7 suborbitals. When writing electron configuration, start at the 1s location and write the address for your element going LEFT to RIGHT. When you reach the end of a row move to the next row. If you pass through an entire orbital you write the last address for the orbital. See the back to an example.

9 ELECTRON CONFIGURATION Example: Titanium (Ti) 1s 2, 2s 2, 2p 6, 3s 2, 3p 6, 4s 2, 3d 2 [Ar] 4s 2, 3d 2 ** noble gas notation puts in parentheses the last noble gas you pass through when writing the electron configuration, then the address for only the row your element is on** Energy Diagrams Energy diagrams show the suborbitals and the electrons found in them based on the electron configuration for the element. For every suborbital you must draw a. When placing your electron arrows, you must put one arrow in every suborbital spot before doubling up. (Hund s Rule). You also need to make sure that your arrows within the same suborbital are alternating (Pauli s Exclusion Principle). Lastly, you must always fill lowers energy levels before moving on to higher energy levels (Aufbau s Rule). Titanium s is shown below.,,,,,, 1s 2s 2p 3s 3p 4s 3d

10 MOLAR MASS Molar mass (also known as atomic mass if it is a single element) is defined as how many GRAMS are in 1 MOLE of a substance. Molar mass is measured in grams/mole. You use the periodic table to find molar mass. 1) make a list of the element(s) in your substance 2) next count how many of each element you have and write that next to the element in your list 3) look up the atomic mass of each element in your list 4) multiply the # of each element by its mass 5) add all masses together Example: Ca3(PO4)2 ß must distribute the 2 to all elements in the parentheses Ca- 3 x 40 = 120 P- 2 x 31 = 62 O- 8 x 16 = g/mol

11 THE ATOM The atom is the smallest form of matter. It is comprised of protons, electrons, and neutrons. Protons and neutrons are found in the nucleus, while electrons are found in orbitals floating around the nucleus. The protons and neutrons are used to calculate an atoms mass. Protons have a POSITIVE charge Electrons have a NEGATIVE charge Neutrons have a NEUTRAL charge APE: Atomic Number=Proton Number=Electron Number MAN: Mass= Atomic Number (protons) + neutrons PECs: Protons- Electrons= Charge

DENSITY Density is a property of matter that indicates the ratio of mass to volume in a

Density is a PHYSICAL property because it describes a substances physical state.

12 DENSITY Density is a property of matter that indicates the ratio of mass to volume in a substance. Density is a PHYSICAL property because it describes a substances physical state. Density is also an INTENSIVE property, which means it DOES NOT change if the amount of the substance changes. Box A s particles are more packed together To find the volume of an irregular than Box B s, therefore it is more dense and shaped object, subtract to find the will sink further while less dense B would water level difference. sink less or even float.

13 Classification of Matter Can it be physically separated?

14 States of Matter

15 Conversions Conversions are used in chemistry to convert back and forth different units of substances. Molar Mass: the number of GRAMS in 1 MOLE of that substance Avagadro s Number: 6.02x10 23 : the number of ATOMS in 1 MOLE of a substance Grams to Moles Given grams 1mole Molar mass (g) Atoms to Moles Given atoms 1mole Avagadro s # (atoms) Moles to Grams Given moles molar mass (g) 1mole Moles to Atoms Given moles Avagadro s # (atoms) 1mole Grams to Atoms Atoms to Grams Given grams 1mole Avagadro s # (atoms) Given atoms 1 mole molar mass (g) Molar mass (g) 1 mole Avagadro s # (atoms) 1mole

16 Physical and Chemical Properties and Changes Physical Properties: describes its physical state and characteristics. Extensive property: CHANGES when amount changes Intensive property: DO NOT CHANGE when amount changes Chemical Properties: describes how it will react or change Physical Change: occurs when the substance keeps its chemical makeup but changes form Chemical Change: occurs when a substance changes its chemical makeup resulting in a new substance

Chemistry 1-2E Semester I Study Guide

Chemistry 1-2E Semester I Study Guide Name Hour Chapter 1 1. Define the following terms. Matter Mass Law of Conservation of Mass 2. Define and give 2 examples of the following: Pure substance Element Compound