210 likes | 357 Views
The Chemistry of Life. Chapter 6. Atoms and their interactions. Elements – are substances that can’t be broken down into simpler substances. Natural Elements in living things. Major elements in the human body: C, H, O, N Make up more than 96% of the mass of the human body. Trace Elements.
E N D
The Chemistry of Life Chapter 6
Atoms and their interactions • Elements – are substances that can’t be broken down into simpler substances
Natural Elements in living things • Major elements in the human body: C, H, O, N • Make up more than 96% of the mass of the human body
Trace Elements • Trace: Ca, P, K, S, Na, Cl, Mg, Fe, Zn, Cu, I, Mn, B, Cr, Mo, Co, Se, F • Vital role in maintaining healthy cells
Atoms: the building blocks of elements • Atom – smallest particle of an element that has the characteristics of that element • Structure effects their properties and chemical behavior
Nucleus – center of the atom • Protons – positive charge • Neutrons – neutral charge • Electrons – around nucleus w/ negative charge
Electron Energy Levels • 1st – can hold 2 electrons • 2nd – can hold 8 electrons • 3rd – can hold 8 electrons • Are there other energy levels?
Isotopes • Atoms that have the same # of protons, but a different # of neutrons • Named by # protons & neutrons (combined total) • EX: carbon-12 vs. carbon-14
WHY Isotopes are useful to scientists • Some nuclei of isotopes are unstable and break apart. • Give off radiation. • Can be used in medicine to diagnose or treat some diseases.
Compounds • Bonding – determined by valence electrons. • 2 or more different atoms chemically combined in a specific ratio.
Covalent Bonds • Electrons are shared & creates a molecule
Molecules • A group of atoms held together by covalent bonds • Ex: Water (H2O)
Ionic Bonds • Ionic bonds – electrons are gained or lost by individual atoms. • Ions are formed. • Ex: Salt: • Ionic Bond b/t Na+ & Cl-
Ions • An ion is a charged particle made of atoms • Atoms that gain or lose electrons have an electrical charge.
Chemical Reactions • Mixture – a combination of substances in which chemicals retain their original properties.
Chemical Reactions • Metabolism – all chemical reactions that occur within an organism
Chemical Reactions • Solution – mixture in which substances are evenly distributed in another substance • Solutes – the substances that are dissolved • Solvent – the substance that things are dissolved in
Chemical equations Ex: 2H2 + O2 2H2O • Large numbers mean how many atoms / molecules of a compound you have • Small numbers indicate how many of that type of atom you have • Symbols are chemical symbols from the periodic table
pH • pH – the measure of how acidic or basic a solution is.
pH • Acid – any substance that forms hydrogen ions in water (H+); pH of below 7 • Base – any substance that forms hydroxide ions in water (OH-); pH above 7