Structure and Properties of Matter

1. Structure and Properties of Matter Georgia High School Graduation Test: Science Review

2. 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)

3. 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

4. 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

5. Atomic Structure • Looking at the periodic table on the GHSGT review sheet: • 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?

6. 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

8. 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

9. 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)

10. “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

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

12. 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.

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

14. 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.

15. 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.

16. 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.

17. 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)

18. Figure Reference • Atomic Number figure: retrieved from http://education.jlab.org/glossary/atomicnumber.html • Atomic Structure figure: retrieved from http://www.rstp.uwaterloo.ca/manual/matter/atom_structure.htm • Periodic Table figure: retrieved from http://www.cameco.com/uranium_101/fact.php