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

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 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 (+) Protons (+) Neutrons (neutral) Neutrons (neutral) Electrons (-) Electrons (-) Most of the mass is concentrated in the nucleus (location of protons & neutrons)

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

Atomic Structure atomic number = number of protons Silver has 47 protons Silver has 47 protons atomic mass = number of protons + neutrons Silver has 61 neutrons Silver has 61 neutrons valence electrons = electrons in the outermost energy level

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?

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

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

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

“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: examples: water and salt water and alcohol polar molecules DO NOT dissolve non-polar molecules examples: examples: oil and water gasoline and water

Sample Questions 1.What are the two parts of an atom? Answer: The two parts of an atom are the nucleus and electron cloud.

Sample Questions 2.Where are the electrons located in the atom? Answer: The electrons move rapidly through the electron cloud that is divided into energy levels.

Sample Questions 3.What is the nucleus composed of? Answer: The nucleus is composed of positive protons and neutral neutrons.

Sample Questions 4.Where is most of the mass of an atom concentrated? Answer: Most of the mass of the atom is concentrated in the nucleus.

Sample Questions 5.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.

Sample Questions 6.Compare and contrast solute and solvent. Answer: Solute is being dissolved and solvent does the dissolving. Typically there is more solvent than solute.

Sample Questions 7.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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