Chem - Summer Biology Chapters 2 3 Atoms \u25cf Atoms fundamental building blocks of matter \u25cf Nucleus \u25cf \u25cb Positively charged protons \u25cb Uncharged

Chem - Summer Biology Chapters 2 3 Atoms u25cf Atoms...

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Summer Biology Chapters 2 & 3 Atoms Atoms: fundamental building blocks of matter Nucleus Positively charged protons Uncharged neutrons (except for hydrogen) Electrons: move around the nucleus Negatively charged Atoms come together to make molecules, which then come together to make macromolecules, which then come together to form organelles, which then form cells 2 electrons fit into the first energy level 8 electrons fit into the second energy level 8 electrons fit into the third energy level Valence electrons: the electrons on the outer shell This is the only thing we care about The valence shell is what makes the electron stable and what makes the bonds Atoms with unpaired electrons in their outermost shell interact with other atoms to make sure they have 8 valence electrons They donate, accept, or share electrons to eliminate vacancies Lewis dot diagrams are pretty important To place the electrons you go counter clockwise, if theres more than 4, go one more time Two electrons on the same side are called a “lone pair” or just a pair An atom with equal numbers of protons and electrons has no net charge Ions (positive or negative) Atoms that have gained or lost electrons Electronegativity How much those atoms attract other electrons The periodic trend for electronegativity increases as you go to the right and as you move upwards Fluorine is the most electronegative and Francium is the least electronegative Hydrogen bonds covalently (it does not ‘demand’ electrons)
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Bond types Ionic - the positive negative stuff Covalent - sharing Hydrogen Hydrogen Bonds: form between a hydrogen atom and an electronegative atom, each with a separate polar covalent bonds. Each have separate polar covalent bonds Do not make atoms into molecules Individually weak Collectively stabilize structures of large molecules Suffixes __ane -- single bond __ene -- double bond __yne -- triple bond Know the meth, eth, prop, bute, etc. sequence Tells the number of carbons Cyclo - the rings of carbon Cyclohexene Has a ring 6 carbons At least one double bond Non - Polar covalent bond Atoms share electrons equally Polar covalent bond Electrons are shared unequally One end slightly negative, other slightly positive Polar molecule has a separation of charge Oxygen does not have a formal charge, but it does have a slightly negative charge δ negative
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