Structure and Properties of Matter

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Structure and Properties of Matter

• Georgia High School Graduation Test Science
  Review
• Mrs. Kirby

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What is an atom?

• the smallest particle of an element that has the
  properties of that element
• element a substance that cannot be broken down
  by ordinary chemical means to a smaller substance
• building block of matter
• Atoms are made of
• Protons ()
• Neutrons (neutral)
• Electrons (-)
• Most of the mass is concentrated in the nucleus
  (location of protons neutrons)

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Atomic Structure

• Nucleus
• contains the protons and neutrons
• where most of the mass of the atom is
  concentrated
• very dense
• Electron Cloud
• the space around the nucleus in which electrons
  move rapidly
• not dense at all
• divided into energy levels
• lower energy levels are closer to the nucleus and
  have less energy

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Atomic Structure

• atomic number number of protons
• Silver has 47 protons
• atomic mass number of protons neutrons
• Silver has 61 neutrons
• valence electrons electrons in the outermost
  energy level

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Atomic Structure

• Looking at the periodic table on page 271, answer
  the following questions
• What element does this atom represent?
• How many valence electrons does this atom have?
• How many neutrons does this element have
  according to the periodic table?

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Isotopes

• atoms of the same element having different
  numbers of neutrons
• identified with different mass numbers
• mass number on the periodic table averages the
  mass of all known isotopes
• isotopes have the same chemical properties

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Periodic Table

• left side metals
• most elements are metals
• right side non-metals
• Groups/Families columns go up and down
• Group number indicates of valence electrons
  (outermost electrons)
• Rows/Periods side to side
• Period number indicates of electron energy
  levels

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Solutions

• solution homogeneous mixture of two or more
  substances that are evenly distributed
• examples Coca-Cola, air, sea water, Kool-aid
• made of solute and solvent
• solute the dissolved substance
• example sugar in iced tea
• solvent the dissolving substance
• example water (universal solvent)

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Likes dissolve likes.

• polar molecules are molecules are partially
  positive on one and partially negative on the
  other end (example water)
• polar molecules dissolve polar molecules
• examples
• water and salt
• water and alcohol
• polar molecules DO NOT dissolve non-polar
  molecules
• examples
• oil and water
• gasoline and water

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Sample Questions

• What are the two parts of an atom?
• Answer
• The two parts of an atom are the nucleus and
  electron cloud.

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Sample Questions

• Where are the electrons located in the atom?
• Answer
• The electrons move rapidly through the electron
  cloud that is divided into energy levels.

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Sample Questions

• What is the nucleus composed of?
• Answer
• The nucleus is composed of positive protons and
  neutral neutrons.

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Sample Questions

• Where is most of the mass of an atom
  concentrated?
• Answer
• Most of the mass of the atom is concentrated in
  the nucleus.

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Sample Questions

• What are the two parts of a solution? Which
  substance is being dissolved? Which substance is
  doing the dissolving?
• Answers
• A solution is made up of a solvent and
  solute(s). The solute is being dissolved while
  the solvent is doing the dissolving.

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Sample Questions

• Compare and contrast solute and solvent.
• Answer
• Solute is being dissolved and solvent does the
  dissolving. Typically there is more solvent than
  solute.

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Sample Questions

• Name some common solutions and tell what is the
  solvent and what is the solute.
• Answer
• sweet tea (solutes are tea and sugar solvent is
  water)
• ocean water (solute is salt solvent is water)

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Short Quiz Answers

1. An atom is the smallest particle of an element
   that has the properties of that element.
2. The nucleus of an atom is much more dense than
   the electron cloud. In other words, the nucleus
   is much more massive.
3. The new atom would no longer be helium it would
   be lithium. The new atom would have a different
   atomic number and much different chemical
   properties.
4. The new atom would be an isotope of helium with a
   larger atomic mass. The new atom would have the
   same chemical properties as the old atom.
5. Likes dissolve likes. means that polar
   molecules dissolve other polar molecules like
   water dissolves salt.
6. A solution is made up of more than one substance.
   It is a mixture.

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More Practice

• Complete the following from the Chapter 2 Review
  Questions (p. 57)
• 2, 5, 6, 7, 16, 18, 20