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Atoms and the Periodic Table

Day 1: Of what are atoms made?

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DO NOW (10 min)

In classroom, complete the TIMELINE REFLECTION!

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DISCOMFORT WHEN READING

The four chemically important types of atomic orbital correspond to values of l = 0, 1, 2, and 3. Orbitals with l = 0 are s orbitals and are spherically symmetrical, with the greatest probability of finding the electron occurring at the nucleus. All orbitals with values of n > 1 and l = 0 contain one or more nodes. Orbitals with l = 1 are p orbitals and contain a nodal plane that includes the nucleus, giving rise to a dumbbell shape. Orbitals with l = 2 are d orbitals and have more complex shapes with at least two nodal surfaces. Orbitals with l = 3 are f orbitals, which are still more complex. Because its average distance from the nucleus determines the energy of an electron, each atomic orbital with a given set of quantum numbers has a particular energy associated with it, the orbital energy. In atoms or ions with only a single electron, all orbitals with the same value of n have the same energy (they are degenerate), and the energies of the principal shells increase smoothly as n increases. An atom or ion with the electron(s) in the lowest-energy orbital(s) is said to be in its ground state, whereas an atom or ion in which one or more electrons occupy higher-energy orbitals is said to be in an excited state. The calculation of orbital energies in atoms or ions with more than one electron (multielectron atoms or ions) is complicated by repulsive interactions between the electrons. The concept of electron shielding, in which intervening electrons act to reduce the positive nuclear charge experienced by an electron, allows the use of hydrogen-like orbitals and an effective nuclear charge (Zeff) to describe electron distributions in more complex atoms or ions. The degree to which orbitals with different values of l and the same value of n overlap or penetrate filled inner shells results in slightly different energies for different subshells in the same principal shell in most atoms.

Open 15-16 Reading… Discomfort...

Read the text, be ready to discuss.

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EXPLAIN

Active Reading Strategy P-L-A-N

1) Predict

2) Locate

3) Add

4) Note

I will be modeling P-L-A-N using a reading on the Development of the Atomic Theory.

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P = PREDICT - Before you read

Pre-read: predict the content and structure of the text using major headings and subheadings as well as bold-face terms

Create a “concept map” using headers and bold items to guide you

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L = LOCATE - Before you read

Assess prior knowledge: locate known and unknown information to help decide how closely they need to read particular sections of text

Determine what you know and ( ) check it.

Put a ( ) question mark next to what you don’t know.

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A = ADD - While you read

Use metacomprehension: briefly explain the new concepts or confirm and extend the known concepts

Add details to your map, explain new concepts, define terms

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N = NOTE - After you read

Work with the information: they may reproduce the map from memory, reorganize the information, summarize the information in a paragraph,...

Summarize the information from the map in a paragraph or list!

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EXPLORE (10 min)

Reading Selection Part 1:

  • Use “PLAN” to READ the reading selection provided in your email.
  • You will need a piece of blank white paper!

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Atoms and the Periodic Table

Day 2: How big is an atom?

What makes an atom?

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ENGAGE

Take out your Graphic Organizer!

Turn to your neighbor and answer 2 of the following questions that were asked before you began reading…

  • What are the three parts of an atom?
  • How are atoms of different elements different?
  • Why are neutrons important?

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Parts of the Atom:

  • Protons - positively charged particles in the nucleus (+1)
  • Neutrons - neutral particles in the nucleus
  • Electrons - negatively charged particles around nucleus (-1)

Atomic Number - Number of protons in the nucleus of an atom.

  • This DEFINES the IDENTITY of the substance (what element it is)
  • Used to locate an element on Periodic Table

Atomic Mass - Average number of protons and neutrons in the nucleus of an atom

  • This give the weight of the atom

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NOTES

This is lithium.

Atomic Number = 3

Protons = 3

Neutrons = 4

Electrons = 3

Atomic Mass = 6.9

This Bohr model is a representation of the Lithium Atom however it is not factually correct. Why?

  • Electrons are much, much smaller.
  • Electrons do not travel in rings. They exist in the "cloud."
  • There is mostly empty space in an atom.
  • If the nucleus of an atom were the size of a baseball, the atomic diameter�would be about 2 miles. The electrons would each be smaller than a period (.)

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More Info

  • The number of protons is not always the same as the number of neutrons.
  • All atoms of the same element have the same number of protons.
  • There are over 115 elements (90 naturally occurring).
  • An atom is mostly empty space.
  • Electrons do not move in perfect circles.

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Why is hydrogen the only element that does not generally have neutrons?

In other words, why are neutrons important?

  • Because protons repel each other, the atoms of every element, except hydrogen, must have neutrons in their nucleus. Neutrons help keep protons from flying apart.

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Notes LINK

Size of the Atom:

1 proton's mass = 1.7 x 10-24 g

This is so small that scientists made up a new unit called the AMU -- atomic mass unit and 1 proton's mass = 1 AMU

  • A million atoms, edge to edge, match the thickness of a page of paper.
  • About 7.5 TRILLION (7.4 x 1012) Carbon atoms fit in one period!
    • Arranged as single graphite crystal, one layer thick

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EXPLORE (cont...)

HW:

Reading Selection Part 2:

  • Use “PLAN” to READ the reading selection provided in your email.
  • You will need a piece of blank white paper!

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Atoms and the Periodic Table

Day 3: How are atoms of elements different? And what forces work inside the atom?

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VOCABULARY

Electron

Proton

Neutron

Nucleus

Isotope

Atomic number

Atomic mass

Bohr model

Ion

Valence electrons

Periodic table

Period

Family

Group

Octet rule

Metal

Metalloid

Nonmetal

Noble gas

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ENGAGE

Quick Check-In

Check Classroom

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NOTES

Ion - charged atom made from losing or gaining electrons

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NOTES

Isotopes - atoms with the same number of protons but a different number of neutrons

These are all hydrogens --- just different isotopes.

Isotopes share most of the same physical and chemical properties. For example, the most common isotope of Oxygen has 8 neutrons, but you can also have 9 or 10 neutrons. All are colorless, odorless, flammable gases and all can keep you alive.

However...

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NOTES

When something

is written like this:

C-14, the “14” is

the MASS NUMBER

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NOTES

HOWEVER WHAT???

There are some differences between isotopes.

  • Some are unstable which means the nucleus will change over time --- this is radioactivity.
  • Isotopes also have different masses from one another.
    • Mass Number = P + N
  • Atomic Mass is the weighted average of the masses of all of the natural isotopes of that element.
    • Of all copper
      • Copper-63 is 69%
      • Copper-65 is 31%
      • The Atomic Mass is 63.6 AMUs

Copper-63

    • 29 protons
    • 34 neutrons

Copper-65

    • 29 protons
    • 36 neutrons

(63 * 69%) + (65 * 31%) = 63.62 AMUs

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NOTES

Four Basic Forces

  • Electromagnetic Force - like charges repel, unlike charges attract
  • Gravitational Force - pulls objects toward one another (because subatomic particles are so small, this has very little effect with atoms)
  • Strong Force - causes protons and neutrons in the nucleus to be attracted to one another
  • Weak Force - in unstable (radioactive) atoms this force plays a role in changing a neutron into a proton and electron.

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More Practice...

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CHECK-IN - (use your Periodic Table in your planner)

  • TELL your table partner how to find the following...
    • Number of protons?
    • Number of neutrons?
    • Number of electrons?

DECIDE with your table partner -

      • Oxygen-2 ?
      • Lithium-1?
      • Magnesium-2?

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Quick Overview

How do I find…

  • # of Protons = Atomic Number
  • # of Electrons in a “Neutral Atom” = # of Protons
  • # of Electrons in Ion = look at Net Charge, if + then subtract e, it - then add e
  • # of Neutrons = Mass - Atomic Number

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HOMEWORK

Complete the Basic Atomic Structure Worksheet.

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Atoms and the Periodic Table

Day 4: Putting it All Together

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EXPLORE

Complete the Build an Atom Activity

  • Open play
  • Explore element cards
    • Discussion

HW: Challenge cards