Name: Mr. Hartman /Ms. Slack Period: Date: Chapter 3 Section 2 The Simplest Matter (Pages 80 85) The Elements There are many different types of atoms. An is matter made up of only one kind of atom. An element is the form of matter. At least elements are known and of them occur naturally on Earth. The Periodic Table To organize and display all of these elements, chemists have created a. The elements in the periodic table are organized by their. means a regular, repeating pattern. History of the Periodic Table French chemist Antoine-Laurent created one of the first lists of elements in the 1790s. (Britain, 1803) used symbols to represent elements and assigned masses to elements. (Russian, 1869) arranged the 63 elements known at the time into groups based on chemical properties. 1
Rows = Periods The rows in a periodic table are called. Elements that are in the same row have the same number of. The number of shells that an element has is equal to the it is in. What is the minimum and maximum number of shells an element can have? Minimum = and Maximum = Columns = Groups The columns in a periodic table are called. Elements that are in the same column have similar related to their structure. How many columns or groups are there in the periodic table? Element Key Each element has its own on the periodic table. The name of each element is represented by a that contains one to three letters. The symbols are a form of chemical shorthand to save and when writing formulas. What is the chemical symbol for: Chlorine: Zinc: Calcium: Nitrogen: Atomic Number The is on the top of the element key. The periodic table is arranged in order of atomic number. 2
The atomic number tells you the number of in the nucleus of each element s atom. What is the atomic number for Chlorine? How many protons are there in an atom of Chlorine? Isotopes The number of determines the element. Adding or removing protons creates a new. The number of protons for each element is always the same, however the number of in an element can vary. are atoms of the same element that have a different number of neutrons. Example: Hydrogen Atomic Mass vs. Mass Number The bottom of the key contains the of the element. The atomic mass of an element is the of the element (in AMUs), taking in account all the isotopes. An atom s is the number of protons + the number of neutrons it contains. 3
Therefore, # neutrons = Example The mass number of an atom of chlorine is 35. How many neutrons are in the atom? Answer = = mass number protons Practice Finding the Number of Neutrons Estimate the number of neutrons for the following elements: Nickel (Ni) Potassium (K) # Neutrons = = Neutrons # Neutrons = = Neutrons How do you find electrons? Since atoms are neutral, electrons are equal to the or the number of protons. Use your periodic table to determine how many electrons are in the following atoms: Nitrogen (N): Magnesium (Mg): Sodium (Na): Bohr Model (Planetary Model) The Bohr Model has the following parts: 4
Orbitals or shells What is the name of this element? How did you figure out which element it is? Name the Bohr Models: Electron Dot Diagram The electron dot diagram is used to model the number of in an element. The dots represent the number of electrons in the shell of the atom. Examples: Classifying the Elements Elements fall into 3 general categories: 1. 2. 3. 5
Metals Most of the elements on the periodic table are. The metals are found on the side of the periodic table. Characteristics of metals: Generally are and have a luster. Good conductors of heat and electricity. All metals, except mercury, are solid at room temperature. They are malleable (can be bent into different shapes) They are ductile (can be stretched without breaking) Nonmetals Except for Hydrogen, the nonmetals are found on the side of the periodic table. Characteristics of nonmetals: Are usually in appearance. conductors of heat and electricity. Many are at room temperature. They are (break easily when bent) Essential to.97% of your body is made of nonmetals. Examples: Oxygen (65%), carbon (18.5%), etc. Metalloids Metalloids are elements that have characteristics of metals AND nonmetals. They are found the metals and the nonmetals on the table (see zig-zag staircase line) Characteristics of metalloids: at room temperature. conductors of heat and electricity. Some used to make in computers, televisions, and other electronic devices. Example:. 6