lec 2 building blocks of life Flashcards
what is an atom?
smallest unit of an element that has some chemical characteristics of that element
what are atoms made of? what are their charges? (3 particles)
protons-positive charge
electrons- negative charge
neutrons- no charge (neutral)
what orbit the nucleus? What does it mean if electron shells are completely full?
electron shells
the atom is stable
what does an atoms chemical identity (# on periodic table) depend on?
number of protons in the atom
what is a bond? what do bonds form?
chemical linkages that hold atoms together to form molecules
why and how do elements form bonds?
form bonds to become stable, they form by taking or sharing electrons from other atoms
what is a covalent bond?
forms when atoms share electrons
what are non-covalent bonds? where do they form? strength of bonds in relation to covalent?
when an atom gains/loses electrons to become more stable (NO SHARING)
form between and within molecules
weaker than covalent bonds
what are 2 main types of non-covalent bonds?
hydrogen, ionic
what type of bonds are hydrogen bonds? what kind of molecules do they form between?
non covalent bonds, form between polar molecules
what are polar molecules?
molecules with uneven pole distrubution (poles are charge of either side if molecule)
what are ions?
atoms that have lost or gained electrons
if an atom gains an electron, what charge does it have?
negative
what are ionic bonds?
bonds that form between atoms of opposite charge
what is an example of an ionic bond?
Salt in water (NaCl + H2O)
what are the 4 major classes of chemical compounds in living organisims?
- sugars
- nucleotides
- amino acids
- fatty acids
why is carbon important? what shapes can it form in?
predominant element in compounds
versatile
can form chains, branches or rings
what is monomer
what element do they contain
small carbon containing molecules, can exist as individual molecules
individual small molecule with 20 or less atoms
