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Published byEdmund Howard Modified over 9 years ago
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Main Idea: All living things are based on atoms and their interactions
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Atoms are: Building blocks of all matter NOT living Similar in structure
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Atoms are made of 3 types of subatomic particles Protons + Neutrons Electrons - Electrons Protons Neutrons
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Nucleus of an Atom Nucleus is the core of an atom. It contains : N Protons Have a positive charge Each type of atom has a specific number of protons (Atomic Number) N eutrons Have no charge / neutral N N Nucleus
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e-e- e-e- Electron Cloud of an Atom The electron cloud is the area that surrounds the nucleus and contains electrons orbit the nucleus of the atom Electrons : have a negative charge Electron Cloud
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Atom Structure +1 Electron Proton Neutron +1
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Subatomic Particle Charge Location
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Subatomic Particle Charge Location Proton + Positive Nucleus Neutron No Charge Neutral Nucleus Electron - Negative Electron Cloud
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Atoms have a balance of positive protons and negative electrons which gives them an overall neutral charge
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+ - An atom or group of atoms that has an electrical charge because it has gained or lost electrons
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+ - An atom can never lose or gain protons because that is its “identification number”.
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+ - BUT An atom CAN lose or gain its electrons. When they do, they become ions.
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Remember – Electrons have a negative charge. If an atom “loses negativity ” it becomes “more positive” If an atom “gains negativity” it becomes “more negative”
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Positive Ions are written with a positive sign. Ex. H+ Negative Ions are written with a negative sign. Ex. OH-
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An atom that does NOT gain or lose electrons has a Neutral charge. It is NOT an ion. Its number of negatively charged electrons is equal to /balanced by the number of positively charged protons. Neutral atoms are written without a sign. Ex. Ra
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Atomic Combinations Main Idea: Atoms join to form elements and compounds
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Element A substance that is made of one or more of the same type of atom. Examples include : O2 – Oxygen we breath O - Oxygen atom 0 3 – Ozone molecule
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Periodic Table of Elements
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Element Symbols Each element is represented by its elemental symbol – a 1-3 letter abbreviation with 1 st letter capitalized
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Compound A substance made of two or more different elements
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Hydrogen atoms - green Oxygen atoms - black Water Molecule Hydrogen Peroxide Molecule
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2 Categories of Compounds – based on whether they contain carbon atoms Compounds that : DO contain carbon atoms - organic compounds DO NOT have carbon atoms- inorganic compounds Carbon Dioxide – CO 2 Water – H 2 O
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Isomers – molecules that have the same type and number of elements but are arranged differently
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Lesson Topic: Chemical Bonding Main Ideas: *Atoms are joined by bonds to form elements and compounds *Bonds involve the atom’s electrons
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Electrons are found in “energy levels ”
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* Each “energy level” only holds a certain number of electrons E level one - 2 electrons E level two - 8 electrons E level three - 8 electrons
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Atoms are reactive (likely to bond) when there aren’t enough valence electrons to fill their outermost energy level. Atoms gain, lose or share valence electrons to fill the level.
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Ionic Bonds Attractive force between oppositely charged ions. Ion – a charged atom due to gaining or losing electrons.
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Compounds formed between Ionic bonds are called ionic compounds. Sodium chloride crystal (NaCl) – Table salt
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How Ionic Bonds Form
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Covalent Bonds Atoms share electrons. Compounds formed by covalent bonds are called molecules.
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Single covalent bond – each atom shares one of its valence electrons Single bonds - Methane
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Double covalent bond – each atom shares two of its valence electrons Double bonds
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Bond energy -the measure of bond strength in a chemical bond. It is the amount of heat E required to break the molecule into its individual atoms. Covalent bonds are stronger than ionic bonds – takes more bond energy to break them apart
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Ionic Bonding https://www.youtube.com/watch?v=n8D6UOefwMo
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