Unit 1: Chemistry of Life Flashcards
(70 cards)
matter
anything that takes up space & has mass
element
a substance that cannot be broken down to other substances by chemical reactions
compound
a substance containing of 2 or more different elements combined in a fixed ratio
essential elements
elements that an organism needs to live a healthy life & reproduce
trace elements
an element indispensable for life but required in extremely minute amounts
atom
the smallest unit of matter that still retains the properties of an element
neutron
a subatomic particle having no electrical charge
electron
a subatomic particle having a single negative electrical charge
proton
a subatomic particle having a single positive electrical charge
nucleus
the center of an atom
dalton
a unit used to measure the size of atoms and subatomic particles
(same as amu: atomic mass unit)
atomic number
number of protons of an element
mass number
sum of protons + neutrons
atomic mass
total mass of an atom
isotopes
different forms of the same element
radioactive isotope
an unstable isotope in which the nucleus decays spontaneously, giving off particles of energy
energy
the capacity to cause change, esp. by doing work
potential energy
the energy that matter possesses bc of its location or structure
electron shells
an energy level of electrons at a characteristic avg distance from the nucleus of an atom
valence electrons
electrons on the outermost electron shell
valence shell
the outermost electron shell
chemical bonds
An attraction btwn 2 atoms, resulting from a sharing of outer-shell electrons or the presence of opposite charges on the atoms.
The bonded atoms gain complete valence shells.
molecule
2 or more atoms held together by covalent bonds
single bond
a pair of shared valence electrons
