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Chapter 14.1 The Structure of The Atom

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Vocabulary Electric Charge Elementary Charge Electron Nucleus Proton Neutron Atomic Number Isotopes Mass number Stable Radioactive

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Electric Charge It was once believed that atoms were the smallest particles of matter We now know that matter consists of three basic particles Proton Neutron Electron Only two of these product an electric charge An electric charge is a fundamental property of matter that can be positive or negative

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Positive and Negative Charges There are two different kinds of electric charges; Positive and Negative Which parts of the atom have a positive charge and which have a negative charge? A positive and negative charge will attract each other Two positive charges will repel each other Two negative charges will also repel each other Opposites attract!!!

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Protons, Electrons, Neutrons

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Elementary Charge An elementary charge is the smallest unit of electric charge in ordinary matter. It is represented by the letter e Atoms can only have whole number electric charge such as +e, -e, +2e, - 3e What are the elementary charges for the pictures to the right?

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Nucleus, Protons, Neutrons, Electrons The nucleus is located at the CENTER of the atom and contains 99% of all the mass and ALL of the positive charge What do you think is found inside the nucleus? Protons, neutrons, or electrons Protons are found in the nucleus and have a positive charge (+e) EXACTLY opposite to the electron Electrons are found inside atoms, but OUTSIDE of the nucleus and have a negative charge (-e) exactly opposite of a proton Neutrons are also found inside the nucleus, but have no electric charge

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The mass of a proton is 1,836 times heavier than an electron!!!

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Forces inside atoms Electromagnetic Force this is causes by the attraction between the electrons and protons Strong nuclear force This is the strongest force known to science. It attracts protons and neutrons to each other at EXTREMELY small distances inside the nucleus Weak nuclear force This is weaker than both electromagnetic forces and strong nuclear forces Gravity This is even weaker than weak nuclear forces inside an atom. Why is gravity so weak in atoms?

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How atoms are different We previously learned that atoms from different elements are all different from one another. A gold atom will have different properties than a silver atom The number of protons are what determine the properties of an atoms. The number of protons is called the atomic number. All carbon atoms have the same number of protons, all hydrogen atoms have the same, etc. How many protons in each of the atoms listed to the right?

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Electric Charge Complete atoms are ELECTRICALLY NEUTRAL. What does this mean? It means that they have the same amount of electrons and protons How many protons and electrons are in a hydrogen atom? Helium atom? Carbon? We also have ions, which have a different number of protons and electrons, therefore they have a charge Positively charged ions have more ____________ Negatively charged ions have more ____________

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Isotopes All atoms of the same element have the SAME NUMBER OF PROTONS, but they can have DIFFERENT NUMBERS OF NEUTRONS ISOTOPES are atoms of the SAME ELEMENT that have different numbers of neutrons A common element that has isotopes is carbon. They are all carbon because they have 6 protons, so what make it an isotope? The ratio between Carbon 14 and Carbon 12 is what is used to carbon date an object

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Carbon Dating What country is the Turin Shroud located in? Carbon 14 was originally what element? How many protons, neutrons, and electrons in Carbon 14 What is half-life? How long is Carbon 14s half-life What is the purpose of using the rings on the trunk of a tree to verify the half-life? Starting at what year does carbon dating no longer work and why?

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Mass Number Again isotopes of the same element have the SAME NUMBER of PROTONS, but a DIFFERENT NUMBER of NEUTRONS. The MASS NUMBER of the isotope tells you the number of protons plus the number of neutrons Aluminum has a atomic number of 13 and a mass number of 27. How many protons and neutrons does this isotope of aluminum have?

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Radioactivity Almost all elements have one of more isotopes that are stable If the nucleus is unstable, it breaks apart. Carbon 12 and Carbon 13 are stable, but Carbon 14 is radioactive because the nucleus is unstable, which is why we use it for carbon dating Radioactivity is a process in which the nucleus spontaneously emits particles or energy as it changes into a more stable isotope Is radiation always dangerous??

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Closing questions What determines what element an atom is? Protons, neutrons, or electrons? What is the difference between the ATOMIC NUMBER and MASS NUMBER? How many neutrons are present in a magnesium atom with a mass number of 24 Find the number of neutrons in a calcium atom that has a mass number of 40?

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Homework Everyone has been assigned a different element You will need to make a model of your atom including the nucleus, the number of protons, neutrons, and electrons MAKE SURE TO HAVE THE RIGHT AMOUNT OF EACH PARTICLE You will then write one paragraph detailing what this element can be used for

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Atom Building Game Neutrons are represented by the BLUE MARBLES Protons are represented by either the RED or GREEN MARBLES Electrons are represented by the YELLOW marbles Each group must build each of the atoms below: Lithium (Li) Carbon (C) Neon (NE) Aluminum (Al)

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The winner of the game is the first player to run completely out of marbles Each player should start with 6 blue marbles, 5 green marbles, and 5 yellow marbles Each player takes turns adding 1-5 marbles, but not more than 5. The marbles may include any mixture of electrons, protons, and neutrons Marbles played in a turn are added to the marbles already in the atom Only atoms where the electrons, protons, and neutrons match one of the naturally occurring elements on the table are allowed. The player must name the element for it to count!!!!