Periodic Table (Darshana Vakharia)

Title: Periodic Table

Principle(s) Investigated:

• The periodic table is a chart containing information about the atoms that make up all matter.
• An element is a substance made up of only one type of atom.
• The atomic number of an atom is equal to the number of protons in its nucleus.
• The number of electrons surrounding the nucleus of an atom is equal to the number of protons in its nucleus.
• Different atoms of the same element can have a different number of neutrons.
• Atoms of the same element with different numbers of neutrons are called “isotopes” of that element.
• The atomic mass of an element is the average mass of the different isotopes of the element.
• The atoms in the periodic table are arranged to show characteristics and relationships between atoms and groups of atoms.

Standards :

PS1.A: Structure and Properties of Matter

• Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms. (MS-PS1-1)

• Each pure substance has characteristic physical and chemical properties (for any bulk quantity under given conditions) that can be used to identify it. (MS-PS1-2),(MS-PS1-3) Supplemental DCI ESS3.C, LS4.D

• Gases and liquids are made of molecules or inert atoms that are moving about relative to each other. (MS-PS1-4)

• In a liquid, the molecules are constantly in contact with others; in a gas, they are widely spaced except when they happen to collide. In a solid, atoms are closely spaced and may vibrate in position but do not change relative locations. (MS-PS1-4)

• Solids may be formed from molecules, or they may be extended structures with repeating subunits (e.g., crystals). (MS-PS1-1)

• The changes of state that occur with variations in temperature or pressure can be described and predicted using these models of matter. (MS-PS1-4)

Materials:

• Element Cards
• Activity Sheet
• Copy of the Periodic Table
• Pair of scissors

Procedure:

Print out the 20 pages of element cards. Laminate each page and cut out the cards. For this lesson you will need the 5 cards for each element from the left side of each sheet. You will also need the card in the upper right corner. This is the atom name card. Tape each of the 20 atom name cards to a spot in the room where students can place the cards that match that atom nearby. For Lesson 4.3, you will need the atom name card, taped in the same location in the room, and the four cards beneath it. Divide the class into 10 groups of 2 or 3 students each.

Each card contains information about one of the first 20 atoms of the periodic table. The students’ job is to read the card carefully, figure out which atom the card is describing, and put the card at the spot in the room for that atom.

Review the information about protons, electrons, and neutrons students need to know in order to match the cards with the correct element:

Proton

Positively charged particle in the nucleus of the atom.

The number of protons in an atom’s nucleus is the atomic number.

Electron

Negatively charged particle surrounding the nucleus of the atom.

The number of electrons surrounding the nucleus of an atom is equal to the number of protons in the atom’s nucleus.

Neutron

Particle in the nucleus that has almost the same mass as a proton but has no charge.

For the atoms of the first 20 elements, the number of neutrons is either equal to or slightly greater than the number of protons.

To match the number of neutrons listed on your card to the correct element, look for an element on the periodic table so that if you add the number of neutrons on your card to the protons of the element, you will get close to the atomic mass for that element. For example, you may have a card that says that the atom you are looking for has 5 neutrons. You would look at the periodic table to find an atom that you could add 5 to its number of protons that would give you a sum close to the atomic mass given for that element. The answer is beryllium (Be), which has 4 protons and an atomic mass of 9.01.

Note: There are a few neutron cards that have two possible correct elements instead of just one:

6 Neutrons—Boron or Carbon

10 Neutrons—Fluorine or Neon

12 Neutrons—Sodium or Magnesium

16 Neutrons—Phosphorous or Sulfur

20 Neutrons—Potassium or Calcium

Student prior knowledge:

Students should know matter is made up of atoms.

Explanation:

Students will begin to look closely at the periodic table. They will be introduced to the basic information given for the elements in most periodic tables: the name, symbol, atomic number, and atomic mass for each element. Students will focus on the first 20 elements. They will try to correctly match cards with information about an element to each of the first 20 elements. Students will then watch several videos of some interesting chemical reactions involving some of these elements. Each box contains information about a different atom. The periodic table shows all the atoms that everything in the known universe is made from. It’s kind of like the alphabet in which only 26 letters, in different combinations, make up many thousands of words. The 100 or so atoms of the periodic table, in different combinations, make up millions of different substances.

Questions & Answers: Give three thought-provoking questions and provide detailed answers.

How is the periodic table organized? Or what is the basis of the arrangement of elements in the periodic table?

The periodic table organizes the elements in horizontal rows or periods by increasing order of atomic number which equals the number of protons in the nucleus of the atom.

What is true of all the elements in the same vertical column?

All the elements of the same column have the same number of valence electrons.

What is the process of gaining or losing electrons to fill the outermost energy level called?

The process of gaining or losing electrons to fill the outermost energy level is called ionization.

Applications to Everyday Life:

The periodic table is an important tool to understand the relationship between the numbers of molecules in chemical reactions. As reactions take place at a molecular level, we need to know about such quantities as concentrations of molecules to understand such phenomena as rates of reactions, equilibria and so forth. To do this, the periodic table is a tool that is used to calculate molecular concentrations. Molecular weight is the sum of the atomic weights of the constituent atoms of the molecule.

Chemical behaviors are related to position of elements in the periodic table, and that knowledge combined with other information is often useful in suggesting alternative choices when looking for reagents with specific properties.

The periodic table must be one of the worlds most frequently used reference tables – if not the most frequently used

Photographs: Include a photograph of you or students performing the experiment/demonstration, and a close-up, easy to interpret photograph of the activity --these can be included later.

Videos: Include links to videos posted on the web that relate to your activity. These can be videos you have made or ones others have made.

Meet the Elements by They Might be Giants

The genius of Mendeleev's Periodic Table