Ch 2 (Chemistry) Flashcards
Matter
-anything that has mass & occupies space
-composed of elements
Atom
smallest unit of an element
atomic number =
the number of protons
ion
atom that gains or loses an electron
cations
-positive charge
-lost 1 or more electrons
anions
-negative charge
-gained one or more electrons
isotope
atom that has gained or lost one or more neutrons
first electron shell
holds 2 electrons
second electron shell
holds 8 electrons
atoms are most stable when
electron shells are completely full
molecule is formed when:
2 or more atoms bond
compound is composed of:
2 or more different elements
molecule:
smallest unit of a compound
chemical bond
sharing or transference of electrons between two atoms
3 types of chemical bonds
-covalent
-ionic
-hydrogen
covalent bonds are formed when:
electrons are shared
ionic bonds are formed when:
electrons are transferred from one atom to another
weak bonds are formed by:
electrostatic attraction between 2 hydrogen atoms
hydrogen bonds form:
in large molecules (protein/DNA) to help stabilize the complex molecular structure
chemical reactions:
formation & breaking of chemical bonds
3 types of chemical reactions
synthesis(anabolism), decomposition(catabolism), exchange of reactions (catabolism followed by anabolism
what influences the rate of a reaction
-concentration of reactants
-temp of the environment
-lower activation energy
-presence of a catalyst protein(enzymes)
organic compounds include:
- C-C & C-H bonds
-covalent bonding
organic compounds are categorized as:
carbohydrates
lipids
proteins
nucleic acids
water
-universal solvent
-ideal transport in living systems
hydrophilic
chemicals that dissolve in water
hydrophobic
chemicals that don’t dissolve in water
Salts
-mineral compounds w/ ionic bonds
-immediately ionize when added to water