Ch. 2 Chemistry Flashcards
big idea: different types of bonds, nomenclature, charged interactions, polarity and electronegativity
what is an element?
a substance that cannot be broken down to other substances through chemical reactions - ex, sodium, chlorine, oxygen
what is a molecule?
a group of two or more atoms [elements] that form the smallest functional unit of a compound
what is a compound?
a substance containing two or more different elements combined in a fixed ratio: NaCl, H20, Co2
what is an isotope?
different FORMS of atoms of ONE ELEMENT: ex carbon 12 has 6 neutrons, carbon 13 has 7, carbon 14 has 8
what is an ion?
a bond formed when one atom takes an electron from another atom
what is an atom?
the smallest part of an element, composed of + protons, - electrons, and neutrons
what is atomic number?
the “name” of an element, based on the # of protons it has. ex: hydrogen has 1 proton, so it has an atomic # of 1
what is mass number?
the # of neutrons in an atom + the # of protons
what is a valence shell?
the outermost shell of an atom, where electrons are that can be taken / shared between atoms
what is an electron?
a negatively charged subatomic particle, responsible for giving charge to atoms
what elements make up the bulk of living organisms?
C , H , O , N , P , S
what is a chemical bond?
an interaction between atoms that holds them together. atoms try to join together in combinations that fill their valence shells
what is a covalent bond?
a bond where atoms equally share electrons
what is a molecular bond?
two or more atoms held together by covalent bonds
what is a single bond?
the sharing of one PAIR of valence electrons (2)
what is a double bond?
the sharing of two PAIRS of valence electrons (4)
what are valence eletrons?
-electrons in the valence shell of an atom
-determines the reactivity of the element
what is electronegativity?
the attraction of an atom for the electrons in a covalent bond: the more electronegative an atom, the stronger it pulls shared electrons towards itself
also dictates the type of bond shared by atoms
what is a nonpolar covalent bond?
a covalent bond where atoms have similar electronegativities = equal sharing
what is a polar covalent bond?
a covalent bond where atoms have unequal electronegativities = unequal sharing, creates partial charges on atoms
what is an ionic bond?
a chemical bond between two IONS. creates IONIC COMPOUNDS, or SALTS
what is a hydrogen bond?
a bond formed when a hydrogen atom covalently bonded to one electronegative atom is attracted to another electronegative atom in a different molecule
what are van der waals interactions?
interactions where transiently positive and negative regions of molecules attract each other
what are hydrophobic interactions?
-when certain macromolecules have hydrophobic portions, they get pushed away by water & do not mix/interact
-ex - cell membranes, oil and water
