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Explore the fascinating world of atoms and elements, from John Dalton's theories to the modern model of an atom. Learn about isotopes, the Periodic Table, and the significance of valence electrons. Dive into the properties of metals and grasp the concept of fusion plasma. Engage in activities to drive home key concepts and enhance your understanding. Uncover the secrets of the atomic world!
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Chapter 4 Elements and the Periodic Table
Atoms and Elements (4.1) • Just like the grouping of spices or candy, the elements have their own spot on the chart.
Elements • Look at the painting, how do you think the artist made the painting?
Theories of Elements • John Dalton-English chemist
Atoms • Atoms: the smallest part of an element that cannot be made smaller. • J.J. Thompson: realized that atoms had negatively charged particles AND positively charged particles.
J.J. Thompson • Believed that atoms had negatively charged particles embedded in positive sphere.
Rutherford • Rutherford shined a beam of light (proton) toward gold foil to prove inside of
Niels Bohr Model and Cloud Model • Thought electrons orbit the nucleus similar to how planets orbiting the sun.
Modern Model of an atom • The nucleus is made of neutrons and protons, surrounded by a cloud of electrons.
Activity • 1. On a piece of paper, make a small circle no bigger than a dime. This represents the nucleus. • 2. Measure the diameter of the circle in centimeters. • 3. Now predict where the outer edge of this model atom would be. • 4. The diameter is around 100,000 times the diameter of its nucleus.
4.2 (Organizing the Elements) • Atomic Number: Every atom of the same element has the same number of protons. The number of protons happens to be the atomic number. • Atomic number of carbon is 6, oxygen is 8, iron is 26.
Isotopes • Remember, all elements have the same number of protons. All elements are also neutral, so they have the same number of electrons as protons. However, they can have different number of neutrons. • Isotopes=elements that have a different number of neutrons.
Isotopes Mass Number=neutrons + protons
Periodic Table of Elements • Similar to a calendar, the Periodic Table of Elements helps us organize elements by their characteristics and properties.
Atomic Mass • Atomic Mass: the average mass of all of the isotopes of an element. Mendeleev
Period: Horizontal Group: Vertical
Plasma • A form of matter that consists of gas-like mixture of free electrons and nuclei of atoms that have been stripped of electrons.
(4.3) Metals • Alkali Metals • Alkaline Metals • Transition Metals
Valence Electrons • Valence Electrons: The outer most electrons that an element has. • Tells us which elements will react strongly with one another