Chapter 4, Atomic Theory WOD are underlined

Each block is an element.

Learn the name and symbol for elements 1-20 (quiz on Friday) Read off the names of the 20 and symbols.

Dalton’s atomic theory 4 parts to describing an Atom. Dalton was not correct but “Close Enough to Count!”

Dalton’s atomic theory 1. Elements are composed of submicroscopic atoms and are indivisible. Smallest part of an element is an atom. Re: The Nuke Thread

Can we divide an atom? What happens if you do?

If you divide an atom smaller than an atom, it stops acting like the element and loses it’s elemental properties. So Dalton was, “Close enough to count”.

Dalton’s atomic theory (Not correct, should be same isotope) 2. Atoms of the same element are identical

Should be: Atoms of the same element have the same chemical properties and are therefore almost identical. OR Atoms of the same isotope are identical. So he was, “Close enough to count”.

3. Atoms can combine with one another in simple whole-number ratios to form compounds (Means water is always 2 H and 1 O.) Compound means “Fixed Ratio” like H 2 0, not like salt water, a mixture of NaCl and H 2 0.

4. Chemical reactions occur when atoms are separated, joined, or rearranged. Atoms are never changed into a different element. Who was the king of alchemy? Midas and his golden touch.

building blocks of atoms: electrons, protons, neutrons WOD’s at end of this section.

Protons positive charge in nucleus, p+ mass 1.0 AMU

Define 1.0 AMU as the mass of 1 proton

Neutrons in nucleus, n o 1.0AMU no charge

Electrons (e - ) are the smallest negative charge mass AMU (count as 0 AMU) 2000 e - = size of 1 p+

Electrons (e - ) are the smallest negative charge Thank you for TV!!!! Purple = magnetic charge Screen is RGB dots. 1 dot is a pixel.

Protons and Neutrons are found in the tiny nucleus. Electrons surround the nucleus in a vast cloud. The electron cloud is many times bigger than the nucleus.

If the nucleus were the size of a marble, then the electron cloud would be the size of What? Guess.

If the nucleus were the size of a marble and placed on the middle of the 50 yard line, then the atom or electron cloud would be the size of Chief’s Arrowhead Stadium

Break up a 2 nd marble into 2000 pieces. For Carbon 12, pick 6 of those pieces and scatter around Arrowhead. Those 6 are the e - cloud.

Nucleus = marble and on the middle of the 50 yard line. Electron cloud = size of Chief’s Arrowhead Stadium. Then WHAT IS MOST of an Atom made up of????

So what is our brains made out of?

Is the wall behind me solid or is it empty space???

In an atom, what is BIG Protons and Neutrons SMALL Electrons (and everything else???)

WOD Definitions: Atom’s Parts: Proton, Neutron, Electron Atomic Mass Unit: AMU, Mass of 1 proton and standard mass measurement. Proton: positive charge, in nucleus, p+, mass 1.0 AMU Neutron: neutral charge, in nucleus, n o, mass 1.0 AMU (think as size = p+) Close enough to count! Electron: negative charge, orbitals (orbit), e -, very small so count as 0 AMU. Nucleus: Center of an atom = p+ and n o.

Memorize Name and Symbol

Atomic number = protons Whole number. It is number of protons in the nucleus of that element He = Atomic number of 2

How many protons does Ne ALWAYS have? Look in inside back of textbook.

Atomic mass = proton + neutrons. total number of protons and neutrons in the nucleus He = Atomic mass of 4

Carbon 14 Name followed by atomic mass. C 14: Name is Carbon which means 6 protons and 6 electrons. 14 means protons + neutrons = 14, i.e., 8 neutrons. What is different about Carbon 12?

Carbon 12 Name followed by atomic mass. C 12: Name is Carbon which means 6 protons and 6 electrons. 12 means protons + neutrons = 12, i.e., 6 neutrons. It has 2 less neutrons than Carbon 14?

HW: Fill out the next page.

Element Name/ Symbol ProtonsMass number ElectronAtomic Number Average Neutron Carbon C Be Ne

Day 2

Day 2: Atomic structure

Element Name/ Symbol Protons WRITE NOTES HERE Mass number WRITE NOTES HERE Electron WRITE NOTES HERE Atomic Number WRITE NOTES HERE Average Neutron WRITE NOTES HERE Carbon C See next page for notes. Be Ne

“Write Notes Here” from previous page. Write the following in the correct places on your HW. Use some twice. p+, e -, n o, = At# = p + + n o = p + (two places) = Mass - At# Pos, Neutral, Neg. Big Small Nucleus Orbits 1 AMU 0 AMU

Isotopes – different numbers of neutrons. Same number of protons, same element. # of Protons or Atomic Number determines the chemical behavior of an element. So Isotopes of the same element behave the same way Chemically. Very hard to separate isotopes. 1 or 2 Pencils in hand of a sprinter.

Isotopes – different numbers of neutrons. Same number of protons, same element, Carbon 12, Carbon 13, Carbon 14 What is H3 or C14 known for?

Average atomic mass – average mass of all isotopes found in nature of an element (shown on P-table)

calculating average atomic mass -number of stable isotopes of that element -mass of each isotope -natural percent abundance of each isotope Formula (mass × decimal abundance) then add together Don’t worry if you don’t follow, we will show several examples.

Fictional element X The above two isotopes are found. What is the average atomic mass of this fictional element X?

The above two isotopes are found. What is the average atomic mass of this fictional element X? 14amu (.7200) + 15amu (.2800)=14.28 amu would be the number on the periodic table

14.28 would be the number on the periodic table NOTES: 1.) does not end in.000, so it must have isotopes. 2.) is closest to 14, so 14 is the most common isotope in nature. 3.).28 is bigger than.000, so the other isotopes are most often 1 bigger than 14. (Approximation, not a law)

A chemical is found to have three isotopes, what is the average atomic mass of this element? 54amu 72.00% 55amu 25.00% 57amu 3.000%

A chemical is found to have three isotopes, what is the average atomic mass of this element? 54amu 72.00% 55amu 25.00% 57amu 3.000% 54 amu x amu x amu x = 38.88amu amu amu = amu

On average how many protons does carbon have?

On average how many neutrons does Cl have?

Elements and chemical symbols H=Hydrogen You need to know 1-20 for the test

Another Periodic Table example: Different Periodic tables arrange the info in a different order.

Memorize Name and Symbol

Atomic number = the number of protons in the nucleus Average Atomic mass = the number of protons plus the average number of neutrons in the nucleus

Ernest Rutherford won 1908 Nobel Prize for studies in radioactivity; discovered nucleus in Ernest Rutherford was the first to show that the atom does not have uniform density, and that most of the its mass is located at its center.

Ernest Rutherford-gold foil test proposed dense positively charged nucleus

The Nucleus Show demo with laser light on wall and Bohr atom model. Hold Bohr model in front of projector and draw light on board Showing outline of nucleus. Describe Weds lab with marbles under a cardboard box.

Next Chapter The Bohr Model of the Atom One of the simplest working models of the atom is that developed by Niels Bohr. In this, a central nucleus containing protons and neutrons is orbited by electrons. The electrons are arranged in shells or energy levels.

Extra Material if time permits

Element song

Periodic table- elements arranged according to similarities in their physical and chemical properties

periods – horizontal rows of the periodic table, properties change as you go across period, similar for each period

groups – vertical columns on the p-table, similar properties