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Published byBeatrice Waters Modified over 9 years ago
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Chemistry
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Matter All living things are made of matter Cannot be created or destroyed
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Atoms Smallest unit of an element that still has the same chemical properties Three subatomic particles – Protons + (inside nucleus) – Neutrons 0 (inside nucleus) – Electrons – (outside nucleus)
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Periodic Table Letter is the atomic symbol Atomic number is how many protons the atom has Atomic mass is the number of protons and neutrons In a neutral atom protons And electrons will be the same
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Element substances that can’t be broken down chemically into simpler substances Examples- – Hydrogen – Oxygen
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Molecule 2 or more atoms come together to make a molecule Examples – H 2 – H 2 O – C 4
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Compound 2 or more elements together in a fixed ratio. Examples: – H 2 O, NH 3, NaCO 3 – For every 1 oxygen, there are 2 hydrogens – All compounds are molecules, but not all molecules are compounds
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Electron shells Areas of electrons around the nucleus Atoms have 2 electrons in the first shell 8 in the following shell Sulfur can bond with 2 other molecules
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Valence Electrons The amount of electrons in the outer shell Determine chemical properties Determine how many bonds they can make
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Valence Electrons When outer most energy shell is not full, atoms find ways to fill energy shells by taking, giving away or sharing electrons
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Lewis Dot Diagrams An easy method to show outer energy shell and predict how the elements will bond together. Shows valence electrons only
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Types of bonds Ionic Bonds- One or more electrons get passed to another element Very weak bond Na will pass one e- Chlorine will accept one e-
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Types of bonds Covalent bonds- Share electrons between two elements Very strong bond – Polar covalent- shares electrons unequally (will be a charge) – Non-polar covalent- shares electrons equally
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Types of bonds Hydrogen bonds- attractive interaction of a hydrogen atom with an electronegative atom hydrogenelectronegative Weak by itself Strong when there are many Water depends on H-bonds
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Chemical reactions (rxn) Making or breaking of chemical bonds Reactants- left side of the equation, what goes into reaction Products- right side of the equation, what comes out of the reaction Comment: All atoms in the reactants must be accounted for in the products
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Chemical rxn examples 2H 2 O 2H 2 + O 2 H + Cl HCl Number at front means 2 water molecules Subscript numbers represent the amount of H in the molecule
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Biochemistry Study of compounds found in living things Organic compounds- always contain Carbon Important Elements in Biology: HONC P S HONC for Biology!!
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Metabolism All chemical activities and changes that happen in a cell or organism – synthesis: building up – decomposition: breaking down
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Types of reactions Synthesis rxn- Simple molecule + simple molecule Complex molecule Decomposition rxn- Complex molecule simple molecule + simple molecule
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Bonds Making complex molecules takes energy! Breaking down a complex molecule releases energy!
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Homework/Classwork Draw one square from the periodic table on a half sheet of computer paper. Include: – Atomic number – Atomic mass – Name of element – Lewis Dot diagram – 5 pictures of molecules that include your element – 3 reasons why your element is important in Biology (being part of living things is not enough)
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