Drill What do you know? 1. Write your definition of an ATOM. 2. What is inside an atom? 3. What determines the identity of an atom?

Drill What do you know? 1. Write your definition of an ATOM. 2. What is inside an atom? 3. What determines the identity of an atom?

Drill 10/6 1. What is inside an atom? 2. What determines the identity of an atom?

The Atom

Objectives - MSFWBAT A. correctly use the following terms: atom, ion, isotope, subatomic particle, atomic number, mass number, average atomic mass, atomic mass unit B. ID and calculate # of protons, neutrons, and electrons in any atom

What is an atom? We know that an element is a substance that cannot be separated into simpler substances An atom is the smallest unit of an element that maintains the chemical properties of that element.

Gold = Element Atoms of Gold

How little is an atom??? If you expand a hydrogen atom to the size of an apple, the apple would expand to the size of the Earth. is to as is to

How little is an atom??? A human hair is about 1 million carbon atoms wide. A speck of dust contains about 3 trillion atoms.

Atoms of Gold Gold = Element Each Individual Gold Atom

The nucleus is a very small region in the center of the atom that is made up of protons and neutrons Surrounding the nucleus are electrons

Inside the atom Subatomic Particles: Particle Charge Mass (kg) Relative Mass (amu) Proton Positive 1.7x10-27 1 Neutron Neutral 1.7x10-27 1 Electron Negative 9.1x10-31 0

Protons: An atom s identity is determined by the number of protons. If you change the number of protons, you change the element. Neutrons: Neutrons maintain stability. If you change the number of neutrons, you have an ISOTOPE. Electrons: Electrons determine an atom s behavior. If you change the number of electrons, then you have an ION.

What the Periodic Table tells us! Atomic Number (Z): 3 Li Lithium 6.941 The number of protons An atom, which is neutral, will have an equal number of protons and electrons so that the positive and negative cancel out (not true for ions)

What the Periodic Table tells us! 3 Li Lithium 6.941 Average Atomic Mass: The weighted average of the atomic masses of the naturally occurring isotopes of the element The Average Atomic Mass rounded to a whole number is the MASS NUMBER Because protons and neutrons are much larger than electrons, they are the only 2 particles that impact the mass of the atom. Therefore: Mass Number = # of protons + # of neutrons # of neutrons = Mass Number - # of protons

What the Periodic Table tells us! Average Atomic Mass: The weighted average of the atomic masses of the naturally occurring isotopes of the element Isotopes are atoms of the same element that have different masses (ie same protons, different neutrons) Isotopes are written using the name of the element followed by a hyphen and then the mass number. (Ex: Hydrogen-1, Hydrogen-2, & Hydrogen-3) OR Write the symbol with the mass # in the upper left corner (Ex: 1 H, 2 H, & 3 H). In this format the atomic # can electively be added in the lower left corner.

10.7 objectives determine average atomic mass from relative abundancies of different isotopes

What is a weighted average? Mrs. Tang s English Class: 20% Homework 45% Test 35% Essay If Sue got a 94% on Homework, a 82% on Tests, and a 89% on Essays, what is her English grade?

What is a weighted average? Sue s English Grade: Homework: (.20)(.94) = 0.19 Test: (.45)(.82) = 0.37 Essay: (.35)(.89) = 0.31 Add all three up and you get: 0.19 + 0.37 + 0.31 = 0.87 = 87%

Now let s do an actual example: Copper consists of 69.2% copper-63 and 30.9% copper-65. Calculate the Average Atomic Mass of copper?

Practice

Wrap-up Lab stations cleaned Complete analysis questions for homework Short quiz tomorrow on calculating average atomic mass

Electrons If electrons are added or removed, we have an. ION This is indicated with a + or charge. Since electrons are NEGATIVELY charged, if we have extra electrons the atom will be. NEGATIVE If the atom has lost an electron, the atom will be POSITIVELY charged. Ca 2+ Cl - O -2

Agenda 10.7 Objectives: determine the relative abundance of isotopes of Pennium and the masses of each isotope Use that information to determine the atomic mass of Pennium But first

Short Quiz 10/7 On your own piece of paper, answer the following: 1. If one added 2 protons and 2 neutrons to an atom of the most common isotope of the element with atomic number 2, write out the proper symbol for that atom showing atomic mass and the new atomic number 2. Calculate the average atomic mass of Lead given the following information: 204 Pb 1.400% (204.0 amu) 206 Pb 24.10% (206.0 amu) 207 Pb 22.10% (207.0 amu) 208 Pb 52.40% (208.0 amu)

Pennium

Wrap 10/7 Which of the following pairs are isotopes? Atomic #45 & Rhodium-103 6 Protons & Carbon-14 14 N & 7 electrons (neutral atom) Uranium-232 & 236 U

Warmup: 10.10 Copper is made up of two isotopes, Cu-63 (62.9296 amu) and Cu-65 (64.9278 amu). Given Copper s atomic weight of 63.546, what is the percent abundance of each isotope?

Solution There are two isotopes, which together must add up to 100% of all the isotopes. So the more abundant isotope, Cu-63 we call x, and the less abundant isotope, Cu-65, we call 1- x, because x + (1-x) = 1 Plug these into values as the abundancies into your average atomic mass equation, and solve for x. This will give your first abundance. Then subtract that from 1, which will give you your second abundance.

Objectives 10.10 - msfwbat Contrast the contributions of Democritus, Dalton, Milliken, Thomson, Rutherford, Bohr, Heisenberg and Schroedinger in the development of the modern understanding of atomic structure Contrast the modern understanding of atomic structure with historic understandings

History of the atomic model Today: you will work in groups of 3-4 to research a particular scientist (see handout) Tomorrow: a gallery walk you will review other group s presentations to complete a notesheet I ll give you specific notes on what I want you to know about each scientist, as well

Drill 10.10 Strontium exists in four isotopes with the following abundances: 88 Sr 82.58% 86 Sr 9.860% 87 Sr 7.000% 84 Sr 0.0056% How many neutrons are in each isotope? What is the average atomic mass?

Objectives 10.11 Contrast the contributions of Democritus, Dalton, Thomson, Mosley, Milliken, Rutherford, Bohr and Schrodinger, etc. in the development of the modern understanding of atomic structure Contrast the modern understanding of atomic structure with historic understandings