Presentation on theme: "Use your space bar to advance each section or page As you go through this study guide, please have the periodic table that you were given. You will be."— Presentation transcript:
Use your space bar to advance each section or page As you go through this study guide, please have the periodic table that you were given. You will be filling it in as you go. The Periodic Table of Elements Study Guide
Next Year… Next year you will be in 9 th grade physical science. The periodic chart you have received will be very useful to you next year. As you go through this study guide, you will be filling it in with information that will be very helpful next year. You will want to hold on to your chart.
Test on the atom unit next week The information you will be studying today will be on the test next week. Go through each slide carefully. You can always go back to slides that you dont fully understand. Taking notes as you go is a very good idea. For the test next week, you will be allowed a cheat sheet (a 3x5 card that you will create in class from your notes)
An atom refresher Matter is anything that takes up space and has mass. All matter is made of atoms Atoms are the building blocks of matter, sort of how bricks are the building blocks of houses. Elements are the alphabet to the language of molecules. To make molecules, you must have elements. Elements are made of atoms. While the atoms may have different weights and organization, they are all built in the same way.
You cant just shove all of the electrons into the first orbit of an electron. Electrons occupy something called shells or energy levels. Only so many can be in any certain shell. The number of shells an atom has relates to the period it is located in. The group that an atom is in is related to how many electrons it has in its outer (valence) shell. So lets explore periods and groups in the next few slides. Electrons have special rules….
Periodic Table This table is a remarkable way to show the manifold relationships between differing kinds of elements The modern table was devised in 1869 by Dimitri Mendeleyev He arranged the elements by weight and by their chemical properties
Periodic Table "...if all the elements be arranged in order of their atomic weights a periodic repetition of properties is obtained." - Mendeleyev The next slide shows a few of the elements from the table.
Periods and Groups Horizontal rows in the periodic table are called periods Vertical columns are called groups We will learn later why the elements can be arranged in this fashion based on the arrangements of the electrons outside the nucleus Please note: Some Table of Elements show 18 groups, others show only 8 groups (the transition elements arent always considered to be in groups – you will see both ways in this study guide)
Periods and Groups Sizes of the atoms decrease as we move from left to right across a period (see the next slide) This is due to the increasing number of protons in the nucleus, so the electrical attraction between the nucleus and the orbiting electrons gets stronger and pulls the electrons closer to the nucleus
Periods and Groups We can display the table to demonstrate other properties as well As you move from left to right across a period, the ability of the atom to attract another electron increases (See next slide) This property is called electronegativity
Periods Each row is called a period The elements in each period have the same number of shells Please make a note on your chart to help you remember that whatever period an element is in, that is how many shells it would have.
Groups Each column is called a group Each element in a group has the same number of electrons in their outer orbital, also known as shells. Except for He, it has 2 electrons The electrons in the outer shell are calledvalence electrons Group 18 or 8 = Filled shells Group 13 or 3 = 3 electrons
Transition Metals Transition Metals have slightly different rules for shells and valence electrons. This is something you will learn about in High School Chemistry.
Determine the number of shells and the number of valence electrons for:
Helium is the exception in Group 8. Since it has just one shell, that shell can only fit 2 electrons instead of 8. It is in this group because all the elements have a full outer shell.
3 Li Lithium 7 Protons = 3 Neutrons = 4 (7-3=4) + + + - - - Electrons = 3 2 in the 1 st shell, 1 in the 2 nd shell Review
Be sure to have all your answers on your study guide worksheet. Remember, if you dont understand a section, you can always go back and redo it.
Groups and Families All the elements in a column have remarkably similar chemical properties Some of the columns have been given special names to distinguish them (We call them families) As you go through the families, very lightly color each family a different color. If you dont have colored pencils with you, make a note to do it later when you do have them. (please…as you color the families, make sure it is very light and not so dark that you cant see the numbers and symbol)
Alkalie Family The first group (Group 1) is called the alkali metals or Alkalai Family. They are the most chemically reactive of all the metals. This group does not include Hydrogen, however. Hydrogen is in its own group. Each element in this family has one valence electron. Generally, if members of this family form an ion, they would have a +1 charge because of their tendency to give away one electron. Please label the first group on your periodic table.
Alkaline-Earth Family The second group is the alkaline-earth metals. They are also very chemically reactive, but not as much as the group in the Alkali family. Each element in this family has two valence electrons. Generally, if members of this family form an ion, they would have a +2 charge because of their tendency to give away two electrons. Please label the second group on your periodic table.
Transition Metals The transition metals and arent considered a family and arent named. (remember some charts will call these Groups 3-12) Members of this group generally have 1, 2 or 3 valence electrons. Generally, if members of this family form an ion, they would have a +1 or +2 or +3 charge because of their tendency to give away one, two, or three electrons. Make a small note on your table to help you remember they are called the transition metals.
Boron Family Group 3 is the Boron Family. (13 on some charts) Each element in this family usually has three valence electrons. Generally, if members of this family form an ion, they would have a +3 charge because of their tendency to give away three electrons. Please label the this group on your periodic table.
Carbon Family Group 4 is the Carbon Family. (14 on some charts) Carbon is the backbone of all living things, Silicon is the backbone of computerized things. Each element in this family usually has four valence electrons. Generally, if members of this family form an ion, they would have a -4 charge because of their tendency to attract four electrons. Please label the this group on your periodic table.
Nitrogen Family Group 5 is the Nitrogen Family. (15 on some charts) Each element in this family usually has five valence electrons. Generally, if members of this family form an ion, they would have a -3 charge because of their tendency to attract three electrons. Please label the this group on your periodic table.
Oxygen Family Group 6 is the Oxygen Family (16 on some charts) Each element in this family usually has six valence electrons. Generally, if members of this family form an ion, they would have a -2 charge because of their tendency to attract two electrons. Please label the this group on your periodic table.
Halogen Family Group 7 are the halogens (Salt Formers) Elements in this group are the most reactive of the non- metals. (17 on some charts) Each element in this family usually have seven valence electron. Generally, if members of this family form an ion, they would have a -1 charge because of their tendency to attract one electron. Elements in this family have a tendency to chemically react strongly with metals. The product of that chemical reaction is a salt. Please label the this group on your periodic table.
Noble Gas Family Group 8 (18 on some charts) are the noble gases and are basically inert (inert means unable to chemically react with other elements) Elements in this family all have filled valence shells. Helium has just two electrons, and they fill its outer shell. The rest of the noble gases have 8 electrons in their outermost shells. (see the next slide) These elements rarely or never form ions or join into chemical reactions. Please label the this group on your periodic table.
Octet Rule The Octet Rule states that atoms cannot have more than 8 electrons in their outermost shell. So that means that starting with the fourth shell, the atom flips any extra electrons to the previous shell. For example, Krypton is in the fourth shell: - 2 electrons fill the first shell - 8 electrons fill the second shell - 18 electrons fill the third shell (10 were flipped from the fourth shell) - 8 electrons in the fourth shell
Electron Shell Examples Showing the Octet Rule Zink (Zn) 2 electrons in the 1st shell 8 electrons in the 2 nd shell 18 electrons in the 3 rd shell 2 electrons in the 4 th shell Bromine (Br) 2 electrons in the 1st shell 8 electrons in the 2 nd shell 18 electrons in the 3 rd shell 7 electrons in the 4 th shell
The Rare Earth Elements (or Inner transition metals) are in periods 6 and 7, and are pulled out to make the Table more compact. Please label the Rare Earth Elements
Thought Questions Think carefully about your answers Why are there only two elements in the first period? Why are there eight elements in the second and third periods? Why do we jump to eighteen in the fourth period? Why are the chemical properties of a group so similar?