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Chemistry of Matter. 8th Grade Science School Year 2003-2004 Luther Burbank School Mr. Frank Canzolino Room 204. 8 th Grade Science. Week 2 Day 6 Tuesday September 2, 2003. Question of the Day.
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Chemistry of Matter 8th Grade Science School Year 2003-2004 Luther Burbank School Mr. Frank Canzolino Room 204 Chemistry Chapter 1.ppt
8th Grade Science • Week 2 • Day 6 • Tuesday • September 2, 2003 Chemistry Chapter 1.ppt
Question of the Day • While trying to bond, what happens if the outer energy level of an atom is not completely filled? What is the resultant structure called? Chemistry Chapter 1.ppt
Question of the Day • While trying to bond, what happens if the outer energy level of an atom is not completely filled? What is the resultant structure called? • The atom will either give up an electron or grab an electron. The resultant structure is called an ion. Chemistry Chapter 1.ppt
Bill Nye the Science Guy Atoms Chemistry Chapter 1.ppt
Electrons and Bonding • It is the outer arrangement of electrons (valance) that determine if elements will form chemical bonds. • First level holds a total of two electrons when fully filled • Second level eight more than the first level for a total of 8 electrons when fully filled • Third level holds eight more than the second for a total of 8 electrons when fully filled Chemistry Chapter 1.ppt
Fill ‘er Up • Build the Periodic Table Chemistry Chapter 1.ppt
Fill ‘er Up (First 2 Periods) Chemistry Chapter 1.ppt
Homework–Fill ‘er Up (3rd Period) Chemistry Chapter 1.ppt
8th Grade Science • Week 2 • Day 7 • Wednesday • September 3, 2003 Chemistry Chapter 1.ppt
Question of the Day • How many electrons are in the first energy level? How many are in the second level? The third? How many total electrons are in the first 3 energy levels? Chemistry Chapter 1.ppt
Question of the Day • How many electrons are in the first energy level? How many are in the second level? The third? How many total electrons are in the first 3 energy levels? • The first energy level has two electrons, the second eight, the third has eight for a total of 18 in the first three levels. Chemistry Chapter 1.ppt
Homework–Fill ‘er Up (3rd Period)–Answers Chemistry Chapter 1.ppt
Ionic Bonding • Ionic bonding involves the transfer of electrons from one element to another. Chemistry Chapter 1.ppt
Ionic Bonds • Ionic bonds involve the transfer of electrons between atoms. • One atom will give up an electron • One atom will gain an electron Chemistry Chapter 1.ppt
Ionic Bonds • In nature, opposites attract • Na+1 will attract F-1 and form an ionic compound NaF • What will happen if Mg and F try to combine? Chemistry Chapter 1.ppt
Ionic Bonds • What will happen if Mg and F try to combine. • We know from the previous example (and the period table) that F will form F-1 • From the periodic table, we see Mg has 2 outer (valence) electrons that is wants to give up and its ion is Mg+2 • We need two ions F-1 to combine with one ion of Mg+2 to make a neutral compound of magnesium chloride • The resultant compound is written MgF2 Chemistry Chapter 1.ppt
Ionic Bonds • Can you think of one every day material that has an ionic bond? Chemistry Chapter 1.ppt
Ionic Bonds • Can you think of one every day material that has an ionic bond? • Table salt is made by ionic bonds and is written NaCl. Chemistry Chapter 1.ppt
Energy for Ion Formation • For an positive ion to form (giving up an electron), the attraction between the positive nucleus (protons) and the negative (valence) electrons must be overcome. Chemistry Chapter 1.ppt
Energy for Ion Formation • Energy is absorbed for a negative ion to form and energy is released for a positive ion to form. • Why must the energy absorbed? • Why is the energy released? Chemistry Chapter 1.ppt
Arrangement of Ions in Ionic Compounds • Opposite charged ions strongly attract • Like charged ions strongly repel • This caused the ions in an ionic compound to arrange themselves in a certain way • Positive ions will tend to get as far away from other positive ions, and will tend to be close to negative ions. Chemistry Chapter 1.ppt
Arrangement of Ions in Ionic Compounds • The ions in an ionic compound will tend to arrange themselves in a regular, repeating way. • This arrangement is called a crystal lattice Chemistry Chapter 1.ppt
Arrangement of Ions in Ionic Compounds • Attributes of ionic compounds • Regular and repeating • Huge number if ions • Crystal lattice • Great stability • High melting points • Chemical formula shows ratio of ions present • Each compound has a particular shape Chemistry Chapter 1.ppt
Homework • Read pages 16-20 • Do page 20, #2, 3. Chemistry Chapter 1.ppt
8th Grade Science • Week 2 • Day 8 • Thursday • September 4, 2003 Chemistry Chapter 1.ppt
Question of the Day • Given the list below, predict which elements will form ionic bonds, and with which other elements. Write the chemical formula. • Na, Al, Br, Be, Cl, F, S Chemistry Chapter 1.ppt
Question of the Day • Given the list below, predict which elements will form ionic bonds, and with which other elements. Write the chemical formula. • Na, Al, Br, Be, Cl, S • NaCl, NaBr, Na2S • BeCl2, BeBr2, BeS • AlCl3, AlBr3, Al2S3 Chemistry Chapter 1.ppt
Homework–Answers • Page 20, #2 • How does an atom become a negative ion? A positive ion? • The atom gains one or more electrons to form a negative ion. The atom loses one or more electrons to become a negative ion, Chemistry Chapter 1.ppt
Homework–Answers • Page 20, #3 • What is ionization energy? What is electron affinity? • The energy required to remove an electron from an atom is the ionization energy. • The tendency to attract an electron to an atom is the electron affinity. Chemistry Chapter 1.ppt
Covalent Bonds • Ionic bonds have atoms that give up or grab electrons. • Atoms tending to form ionic compounds tend to be at opposite sides of the periodic table • Covalent bonds have atoms that tend to share (not transfer) electrons • Where on the periodic would you expect covalent bonds to occur? Chemistry Chapter 1.ppt
The Nature of Covalent Bonds • The positively charged nucleus attracts the negatively charged electrons at the same time • Electrons spend most of their time between the atoms Chemistry Chapter 1.ppt
8th Grade Science • Week 2 • Day 9 • Friday • September 5, 2003 Chemistry Chapter 1.ppt
Test–Atoms and Ions • Instructions • No books, you may use your three ring binder and any notes or other information it contains • Typographical error, page 35, right hand True-False question • Says tow • Should be two • Print Name, Date & Period at the top of front page • Hand in when complete then read pages 20–31 • Absolute silence until everyone has handed in the test Chemistry Chapter 1.ppt
True or False The electrons in the outermost electron energy level of an atom are called valence electrons. T F The atomic number on the periodic chart tells us how many neutrons are in the nucleus. T F True or False Ionic bonding involves the transfer of electrons between two atoms T F Atoms are the smallest unit of matter where a material is distinct (an element). T F Test–Atoms and Ions Chemistry Chapter 1.ppt
How many naturally occurring elements are there? How many known elements are there? What is the difference between the two? When you combine two different elements, a new substance is formed. What is the combining process called? Test–Atoms and Ions Chemistry Chapter 1.ppt
What are the three particles of the atom? _________ _________ _________ What are the charges on those particles? ________ ________ ________ Test–Atoms and Ions Chemistry Chapter 1.ppt
Test–Atoms and Ions • In words, describe the structure of the atom, and draw and label a sketch illustrating your words. Chemistry Chapter 1.ppt
Test–Atoms and Ions • How many electrons completely fill the first electron energy level and on what element would that occur? • How many electrons completely fill the second electron energy level and on what element would that occur? • How many electrons completely fill the third electron energy level and on what element would that occur? Chemistry Chapter 1.ppt
Draw the atom (nucleus and electron energy levels) for Na atom. Draw the atom (nucleus and electron energy levels) for Na ion. Test–Atoms and Ions Chemistry Chapter 1.ppt
Test–Atoms and Ions • Draw the electrons in the energy levels of magnesium (Mg). Do the same for oxygen (O). Given the number of valence electrons for each element, what do you think the chemical formula is for magnesium oxide? Repeat for calcium oxide and calcium sulfide. Chemistry Chapter 1.ppt
Test–Answer • Draw the electrons in the energy levels of magnesium (Mg). Do the same for oxygen (O). Given the number of valence electrons for each element, what do you think the chemical formula is for magnesium oxide? (MgO) Repeat for calcium oxide (CaO) and calcium sulfide (CaS). Chemistry Chapter 1.ppt