Name____________________ Date__________________ Science Unit 3 Periodic Table Lesson 1 The Atom Page 158 What makes up matter? Democritis believed that you would eventually end up with a particle that _____________________ be cut. He called this _________________ the Greek meaning “________________________________________”. Page 159 Atoms The _________________ particle into which an element can be diveded and be the same element. Is consided the _____________ unit of matter. You _______________ see individula atoms, but they make up everything you see. Many types of atoms that ___________________ in different ways to make ___________ substances. Atoms are so ___________________ you can’t see them with an ordinary microscope. Name____________________ Date__________________ Science Unit 3 Periodic Table Pg. 160 Atomic Theory John Dalton 1808 Dalton’s theory stated that all ________________ is made of _______________. He believed that atoms cannot be created, ______________, or_____________________. All atoms of certain elements are __________________, but they are ______________________ from atoms of all other atoms. Every substance is made up of atoms ______________________ in certain ways. Pg. 161 J.J. Thomson 1897 Atoms are made up of even ________________ particles. Paricles within the atom have _____________________ charge. The negatively charged particles are called__________________. Atom was __________________ sphere with ______________ mixed through it. Name____________________ Date__________________ Science Unit 3 Periodic Table Ernest Rutherford 1909 Atoms have a _______________-a small, dense _____________ that has a _________________ charge and is surrounded by moving __________________. Later he found the nucleus had __________________ charged particles in the nucleus called __________________. Niels Bohr 1913 Electrons move around a nucleus in a ______________________ paths. Each path is a __________________ distance from the __________________. His model helped scientist predict the ____________________ _________________________ of elements. What is the Current Theory? Atoms are ________________ unit of matter. Atoms of each element are ______________. Atoms are made up of _________________ and protrons. 1932, Chadwick discovered that the nucleus contains uncharged particles called __________________. Electrons move within an area around the nucleus called the _____________________ __________________. Name____________________ Date__________________ Science Unit 3 Periodic Table Pg. 162 What are the parts of an atom? Protrons Are ________________ charged particles of the atom. The charge is written as __________. The mass of a protron is very _________________. The measure unit for them is the _________________ _________________ mass _______ (u). The mass of a protron is ___________(u) Particles that have ________ electric _____________. Is a little more _____________ than protrons are. Atoms usually have at least as many ________________ as they Neutrons do protrons. Together protrons and neutrons for the ______________ in the center of the atom. Pg. 163 Electron Cloud The __________________ charged atom is called electrons. It is not possible to determine both their exact _________________________ and ________________ at the same time. Name____________________ Date__________________ Science Unit 3 Periodic Table Electrons are located in an ______________________ _________________________. Compared to protrons and neutrons, electrons have very little ______________. It is so small that it is usually thought almost ____________. The charge of a single elctron is represented __________. The number of protrons in an atom is ____________ to the number of protrons. The atom has an overall charge of ________. Pg. 164 How can we describe atoms? By Atomic Number The number of ___________________ is the atomic _______________. Pg. 165 By Mass of the Number Atoms of certain element always have the same number of protrons, but not always the same number of ________________. ____________________ are atoms of the same element that have different number of neutrons. The total number of _________________ and ______________________ in an atom is its mass number.