Investigation III: A Particulate World Alchemy Unit Investigation III: A Particulate World Lesson 1: Pudding and Clouds Lesson 2: Building Atoms Lesson 3: Subatomic Heavyweights Lesson 4: Life on the Edge Lesson 5: Shell Game Lesson 6: Go Figure Lesson 7: Technicolor Atoms

Alchemy Unit – Investigation III Lesson 1: Pudding and Clouds

Periodic Table Groups Group 1- Alkali Metals- these are very reactive. Have even been know to explode when water touches them. Sodium Carbonate Unit 1 • Investigation III

Group 2- Alkaline Earth Metals Periodic Table Groups Group 2- Alkaline Earth Metals They are not nearly as reactive as Group 1 but will form bonds easily. Radium can be found in glow-in–the-dark paint Unit 1 • Investigation III

This group will not form bonds with other atoms. Periodic Table Groups Group 6- Noble Gases This group will not form bonds with other atoms. Unit 1 • Investigation III

ChemCatalyst In the 5th century BCE a Greek philosopher named Leucippus and his student, Democritis, stated, “All matter is made up of particles that can’t be divided called atoms.” What do you think atoms are? Unit 1 • Investigation III

The Big Question How have chemists thought about the atom through history? Unit 1 • Investigation III

You will be able to: Describe some models of an atom and explain how they differ. Unit 1 • Investigation III

Notes Atoms are extremely small particles, which cannot be seen, even with microscopes. All matter is made up of atoms. Scientists have created models to describe atoms. Models are similar to theories, but often include a picture or physical representation. (cont.) Unit 1 • Investigation III

As new evidence is gathered, models are refined and changed. (cont.) Scientific evidence is a collection of observations that many people have made. Everyone agrees on the same collection of observations. When a model is supported by scientific evidence it is often accepted by the scientific community. As new evidence is gathered, models are refined and changed. Unit 1 • Investigation III

Parts of the Atom A proton is a positively charged particle that exists in the nucleus. A neutron is a neutral particle with no charge on it that exists in the nucleus The electron is a negatively charged particle that exists in an electron cloud around the nucleus. (cont.) Unit 1 • Investigation III

The Nucleus An atom is mostly empty space. There is the nucleus, which is located in the very center of the atom. The nucleus is very small. . The nucleus is also very dense and consists of two types of particles—neutrons and protons. (cont.) Unit 1 • Investigation III

A cloud around the nucleus where the electrons can be found. Electron Cloud A cloud around the nucleus where the electrons can be found. Unit 1 • Investigation III

Notes (cont.) Unit 1 • Investigation III

Activity Purpose: This lesson will introduce you to various models for the atom that have appeared over the past two hundred years. The descriptions of five models of the atom are on a separate handout. (cont.) Unit 1 • Investigation III

Theories of the Atom The History of the Atom

Atoms can not be divided into smaller pieces John Daltons Theory Matter is made of atoms Atoms can not be divided into smaller pieces Unit 1 • Investigation III

Different elements are made of different kinds of atoms All atoms of an element are exactly alike Unit 1 • Investigation III

John Dalton thought that atoms looked like solid spheres. Unit 1 • Investigation III

J.J. Thomson Thought that the atom is a sphere of positive charge with negative charges spread equally throughout. Therefore, atoms have a neutral charge. Unit 1 • Investigation III

Ernest Rutherford Thought that the atom had a nucleus (center) that was all positive charge and electrons (negative) that float around it. Unit 1 • Investigation III

Neil Bohr Atoms have three particles protons, neutrons and electrons. Electrons exist in shells or energy levels around the nucleus. Unit 1 • Investigation III

Current Nuclear Model Atoms has three types of particles and the electrons exist in an electron cloud. Protons (positive) Neutrons (neutral) Electrons (negative) Unit 1 • Investigation III

Making Sense From Pudding & Clouds: Examine the date of the atomic evidence and then put the five models in the correct order of their introduction to the world of science. Unit 1 • Investigation III

(cont.) Five Models of the Atom Unit 1 • Investigation III

Check-Out Here is a Bohr model of a carbon atom. List two things this model tells you about atoms. List something this model does not tell you about atoms. Unit 1 • Investigation III

History of the Atom Foldable Create a tri-fold with the following information: Each Scientists idea of the atom including the persons name, description of what they thought and a picture of their idea of the atom. Must be colorful and displayable! Will be collected and graded!! Unit 1 • Investigation III

Wrap-Up All matter is made up of extremely small particles called atoms. These particles are too small to be seen even with a microscope. Science is theoretical and dynamic. Models and theories are continually being revised, refined, or replaced with new models and theories. Unit 1 • Investigation III

Alchemy Unit – Investigation III Lesson 2: Building Atoms

Copy these questions into your journal. Look at the following pictures and list three similarities and three differences. Unit 1 • Investigation III

ChemCatalyst A Bohr model of a helium atom and a beryllium atom are given below. Helium, He Berylium, Be (cont.) Unit 1 • Investigation III

The Big Question What does the periodic table tell us about the structures of different atoms? Unit 1 • Investigation III

You will be able to: Use the periodic table to identify the properties of an elements atom. Unit 1 • Investigation III

Atomic Number Atomic number is the number of protons in the nucleus of an atom. This number is above the chemical symbol. The number of electrons is always equal to the number of protons in a neutral atom. Ex. Lithium has 3 protons, therefore it also has 3 electrons Unit 1 • Investigation III

Mass Number Mass number is the number of protons plus the number of neutrons. You can find this by rounding the number beneath the chemical symbol. Also referred to as atomic mass because it is the mass of one atom of the element. Unit 1 • Investigation III

Atomic Weight 1. Atomic Weight is the decimal number that is found beneath the chemical symbol for an element. 2. It is an average of all the different types of atoms for that element. Unit 1 • Investigation III

Calculating the parts of the atom Mass number (# of protons + neutrons) minus Atomic Number (# of protons) ____________________________ Number of neutrons Unit 1 • Investigation III

How to read and use an element key Unit 1 • Investigation III

Activity Purpose: Label where the protons, neutrons and electrons are in these atoms. Beryllium Atom Fluorine Atom Carbon Atom (cont.) Unit 1 • Investigation III

(cont.) element chemical symbol atomic number # of protons # of electrons # of neutrons mass number atomic weight beryllium 5 fluorine 10 6 12 chlorine 18 35.45 lead 126 potassium 19 39 tin 70 tungsten 184 183.85 29 36 gold 118 Unit 1 • Investigation III

Making Sense If you know the atomic number of an element, what other information can you figure out about the atoms of that element? If you know the atomic number of an element, can you figure out how many neutrons an atom of that element has? Can you come up with a close guess? Explain. Unit 1 • Investigation III

Bohrs Models

How to draw a Bohrs Model First, find the number of protons, neutrons and electrons Draw a nucleus Look at the period. This is the number of shells the atom will have. Ex. Elements in Period 2 have two shells Unit 1 • Investigation III

Continued Look at the Group Number, this will tell you the number of electrons in the last (outer) shell Unit 1 • Investigation III

Rules for Bohrs Models There is a maximum amount of electrons that can exist on each level. Shell # 1 (next to the nucleus) can only have up to two electrons Shell # 2 can only have up to 8 electrons Shell # 3 can only have up to 18 electrons Shell # 4 can only have up to 32 electrons Unit 1 • Investigation III

Check-Out 1. Use your periodic table to identify the following elements: a) Atomic number 18 b) Has three electrons c) Atomic mass of 16.0 2. How do you think a gold atom is different from a copper atom? Unit 1 • Investigation III

Wrap-Up Each successive element has one more proton than the element preceding it. The atomic number is equal to the number of protons. (cont.) Unit 1 • Investigation III

(cont.) The number of electrons is equal to the number of protons (as long as the atom is neutral). The mass number is equal to the number of protons plus the number of neutrons (most of the mass is found in the nucleus). Unit 1 • Investigation III

Alchemy Unit – Investigation III Lesson 4: Life on the Edge

ChemCatalyst The three atoms below have similar reactivity and chemical behavior. Where are these elements located on the periodic table? What do you think might be responsible for their similar properties? (cont.) Unit 1 • Investigation III

(cont.) Unit 1 • Investigation III

The Big Question What accounts for the similar chemistry of elements in the same group? Unit 1 • Investigation III

You will be able to: Give the number of valence electrons for an element. Unit 1 • Investigation III

Activity Purpose: The various physical and chemical properties of the elements can be traced to the electrons. By studying electrons further we may be able to unlock the key to creating substances similar to gold. This lesson will reveal the arrangement of electrons within atoms. Unit 1 • Investigation III

(cont.) Five Models of the Atom Unit 1 • Investigation III

Making Sense Explain how you can determine the arrangement of an element’s electrons, from the element’s position on the periodic table. Unit 1 • Investigation III

Notes Bohr proposed that electrons could be found in different shells around the nucleus. Unit 1 • Investigation III

(cont.) (cont.) Unit 1 • Investigation III

The outermost shell of each drawing is called the valence shell. (cont.) The outermost shell of each drawing is called the valence shell. The valence shell contains the valence electrons. All other electrons are considered core electrons. Unit 1 • Investigation III

Check-In Provide the following information for element number 34. a) The element’s name and symbol. b) The number of protons in the nucleus. c) The total number of electrons for this element. d) The number of core electrons for this element. (cont.) Unit 1 • Investigation III

e) The number of valence electrons. (cont.) e) The number of valence electrons. f) The group number for this element. g) The names of other elements with similar chemistry. Unit 1 • Investigation III

Wrap-Up Electrons occupy different shells around the nucleus of an atom. Each electron shell can hold a specific maximum number of electrons. The valence electrons are in the outermost electron shell of an atom. Electrons that are not valence electrons are called core electrons. (cont.) Unit 1 • Investigation III

Elements with the same number of valence electrons have similar chemistry and are in the same group. Unit 1 • Investigation III