Quietly study for your quiz – spelling counts! Element Quiz #1 Quietly study for your quiz – spelling counts! Make sure you write “Element Quiz #1” at the top of the paper, portrait layout, and your name & bell. Number 1 – 11.

Cadmium Be Antimony Bi Arsenic Br Argon Ba Calcium B Aluminum Element Quiz #1 Cadmium Be Antimony Bi Arsenic Br Argon Ba Calcium B Aluminum

Now fill in the nuclear symbol boxes. Draw the Helium atom in your notebook and label it using the terms to the right. Electron Neutron Nucleus Orbital Proton Now fill in the nuclear symbol boxes. He

Follow along in your text Chapter 3 Section 1 Pages 74 - 78 Atomic Theories Follow along in your text Chapter 3 Section 1 Pages 74 - 78

Law of Definite Proportions Every sample of a compound are made with the exact same elements in the same proportions All salt, from a grain to all of the salt in the world is made of 60.66% Cl & 39.34% Na Na Cl

Law of Conservation of Mass Mass of reactants equals the mass of the products 1 lb cheese + 1 lb tortilla chips = 2lbs of nachos O S S + O = S + O2 = SO2

Law of Multiple Proportions Compounds always have a whole number ratio of one element to the other O N NO has the ratio 1 N :1 O O N NO2 has the ratio 1 N :2 O Even though they both just have N & O

Dalton’s Atomic Theory All matter is made of atoms, which can not be divided, created, or destroyed Atoms of the same element are identical in all properties Atoms of different elements differ in all properties

Dalton’s Atomic Theory Atoms of different compounds combine in whole number ratios Chemical Rxns combine, separate, and rearrange atoms but those atoms are never destroyed, created, or changed

Warm-Up Pick the colored sticky note you want and put it on the board under the number you like best. When everyone has posted their note… Find the percent of each number chosen. Multiply the percent of each times each number. Add these two answers together and then divide by 100 Does your final answer reflect an average of these two numbers? Justify.

Follow along in your text Chapter 3 Section 2 Pages 84 - 89 Atomic Structure Follow along in your text Chapter 3 Section 2 Pages 84 - 89

Parts of the Atom Electron – negatively charged particle (e-) Located in electron cloud (orbitals) Very small mass; doesn’t even count! Proton – positively charged particle (p+) Located in nucleus Mass of 1 amu (atomic mass unit) Neutron – neutrally charged particle (n0) Mass of 1 amu

© Addison-Wesley Publishing Company, Inc. Mass Number mass # = protons + neutrons always a whole number NOT on the Periodic Table! © Addison-Wesley Publishing Company, Inc.

Hyphen notation: carbon-12 Isotopes Atoms of the same element with different mass numbers. Nuclear symbol: Mass # Atomic # Hyphen notation: carbon-12

Isotopes have different amounts of neutrons that change the masses! © Addison-Wesley Publishing Company, Inc. Neutrons 6 Neutrons 8

Isotopes Chlorine-37 atomic #: mass #: # of protons: # of electrons: # of neutrons: 17 37 20

Ions (Charged Atoms) Atoms of the same element with different amounts of electrons Negative Ions (Anions) have more electrons than protons Add the charge to the number of protons to get the number of electrons Positive Ions (Cations) have less electrons than protons Subtract the charge from the number of protons to get the number of electrons

The negative sign means it has a negative charge Anions The negative sign means it has a negative charge Charge It has 2 more electrons than protons There are 8 protons & 10 electrons

Cations The positive sign means it has a positive charge (there is not always a plus sign) Charge It has 1 less electron than protons There are 19 protons & 18 electrons 1 39 19 K +

Ca 2 39 20 Ions Use the symbol to answer the below atomic #: 20 mass #: # of protons: # of electrons: # of neutrons: 20 39 18 19 2 39 20 Ca

© Addison-Wesley Publishing Company, Inc. Relative Atomic Mass 12C atom = 1.992 × 10-23 g atomic mass unit (amu) 1 amu = 1/12 the mass of a 12C atom 1 p = 1.007276 amu 1 n = 1.008665 amu 1 e- = 0.0005486 amu © Addison-Wesley Publishing Company, Inc.

Average Atomic Mass Avg. Atomic Mass weighted average of all isotopes on the Periodic Table round to 2 decimal places Avg. Atomic Mass

Average Atomic Mass EX: Calculate the avg. atomic mass of oxygen if its abundance in nature is 99.76% 16O, 0.04% 17O, and 0.20% 18O. Avg. Atomic Mass 16.00 amu

Average Atomic Mass EX: Find chlorine’s average atomic mass if approximately 8 of every 10 atoms are chlorine-35 and 2 are chlorine-37. Avg. Atomic Mass 35.40 amu