Chapter Two Flashcards
atom?
the smallest piece of an element that retains the characteristics of that element
element?
pure substance containing only one type of atom, cannot be broken down by chemical means
molecule?
made up of atoms and is a stable association of atoms, can be composed of one or more elements
compound?
made up of molecules of at least two different elements, NaCl is compound
proton’s charge, mass, and location?
proton has a positive charge, a mass of 1 (amu) located inside the nucleus
neutron’s charge, mass, location?
No charge, mass of 1 amu and it is located inside the nucleus
Electron’s charge, location, and mass?
negative charge located in orbitals 90% of the time and the mass is 0 essentially
atomic number?
the number of protons of the atoms, this identifies the element
atomic weight?
is the average mass of all the isotopes of a particular element
molecular weight?
the sum of all the atomic weights of all atoms in a molecule
mass number?
the number of protons and neutrons in a atoms nucleus
isotope?
an element with the same number of protons but different number of neutrons, so same element may have different mass number
orbital?
region where an electron is located at least 90% of the time, can be occupied by a maximum of 2 electrons
electron shell?
is the energy level
in the shell, orbitals are filled in a specific sequence
1st shell holds 2 electrons 1 orbital
2nd shell holds 8 electrons 4 orbitals
valence shell?
the outermost shell, which determines how the atoms will behave
when is an atom reactive / unstable?
when there are unpaired electrons in orbitals in the outer valence shell
when is an atom stable / non-reactive?
when the valence shell is full
covalent bonds?
when atoms share one or more pairs of electrons so that the valence shell is filled
they are very strong bonds - lots of energy to break them
can have single (one pair), double (two pairs) or triple (three pairs)
50-110 bond energy
polar covalent?
when one atom has a greater electronegativity so the electrons shared in the bonds are more attracted to to that atom’s nucleus.
non polar covalent?
when atoms have same electronegativity so electrons shared in the bond are shared equally.
ionic bonds?
when one atom is much more electronegative, a complete transfer of electrons occurs
the result is two ions, one positively charged and one negatively charged
Ionic bonds are bonds formed from the electrical attractions of positive and negative ions
3-7 bond energy
hydrogen bond?
is an attraction between the positive side and the negative side of another molecule (H2O) is a good example
3-7 bond energy
van der Waals
occurs when adjacent atoms come close enough that the outer electron clouds just barely touch.
bond energy is 1
redox reaction (oxidation-reduction) reaction?
when electrons are transferred between two molecules
if a molecule is reduced it gains a negative charge, or an electron (acceptor/agent that oxidizes)
if a molecule is oxidized it gains a positive charge by losing an electron (electron donor/agent that reduces)
