ATOMS

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ATOMS
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What are elements made of?What makes up ALL
matter?
ATOMS!!
Draw a circle on your paper.
You have 2 minutes to write down everything you
know about atoms!
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An atom is the smallest particle into which an
element can be divided and still be the same
substance.
Aluminum atoms seen through a scanning tunneling
electron microscope.
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What are atoms made of?

• Atoms can be divided into smaller parts called
  subatomic particles.
• Nucleus
• Electron
• Proton
• Neutron
• Electron Cloud

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Protons

• Protons are positively charged particles in the
  nucleus.

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Neutrons

• Neutrons are particles in the nucleus that have
  no electrical charge.
• Neutrons are a little bigger than protons.

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No Charge!
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Nucleus

• Every atom has a nucleus, a positively charged
  center portion.

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Inside the Nucleus

• Both protons and neutrons are found inside the
  nucleus of an atom.

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Outside the Nucleus

• Electrons are the negatively charged particles in
  atoms.

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Electrons are found around the nucleus within
electron clouds.
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• An atom has the same number of protons as
  electrons.

This Lithium atom has 3 protons and 3 neutrons.
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• If a hydrogen atom has 1 proton, how many
  electrons does it have?
• If a nitrogen atom has 7 protons, how many
  electrons does it have?

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What Makes Elements Different?

• Atoms make up individual elements. By changing
  the number of protons in the atom, you change the
  type of element.

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Protons and Electrons are in ALL atoms!

• The simplest atom is made up of just one of each.

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1. Draw one proton in the center of the atom
   (nucleus).

2. Put one electron in the electron cloud.
3. You just drew a hydrogen atom!
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All other atoms have protons, neutrons, and
electrons.

1. Draw two protons in the center of the atom
   (nucleus).

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2. Put two neutrons in the nucleus.


3. Put two electrons in the electron cloud.
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4. You just drew a helium atom!
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Ever heard of an ISOTOPE?

• Atoms can have the same number of protons but be
  missing a neutron or have an extra neutron. That
  type of atom is called an isotope.
• Isotopes are still the same element. They are
  just a little different from every other atom of
  the same element.

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Carbon Isotope
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Atomic Number

• The atomic number is the number of protons in the
  nucleus of an atom.

This Lithium atom has 3 protons, so it has an
atomic number of 3.
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• Every hydrogen atom has only one proton in its
  nucleus, so hydrogen has an atomic number of 1.

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• Every carbon atom has six protons in its nucleus,
  so carbon has an atomic number of 6.

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Your turn
How many protons are in the nucleus of the
following elements?
1.
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2.
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3.
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4.
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Atomic Mass

• The atomic mass is the sum of the protons and
  neutrons in an atom.

PROTONS NEUTRONS ATOMIC MASS
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• We can determine the atomic mass of an element by
  looking at the periodic table.

Hydrogen has an atomic mass of 1.00794
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Your turn
How many protons and neutrons are in the nucleus
of the following elements?
1.
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2.
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3.
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4.
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Lets Look Closer at Electron Clouds

• There are some rules for drawing atoms placing
  electrons in the electron clouds.

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Your Turn!
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Atomic Number

• 1.

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Atomic Mass

• 2.

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Atomic Mass

• 3.

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Atomic Number

• 4.

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Atomic Mass

• 5.

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Atomic Number

• 6.