Chapter 2 Flashcards
occupies space and has mass
matter
quantity of matter in an object
mass
purest form of matter
element
fundamental unit of matter
atom
3 parts of an atom
proton, neutron, electron
protons and neutrons are found in
the nucleus
protons and neutrons have
one atomic mass unit
electrons are found in
clouds around the nucleus
electrons have
no mass
number of protons in the nucleus
atomic number
number of protons and neutrons
atomic weight
different number of neutrons than original
isotopes
has the same number of protons and electrons
isotopes
unstable and emits energy
radioactive isotopes
atoms coming together forming molecules
chemical bonding
what are the 3 types of bonds?
- Covalent
- ionic
- hydrogen
atoms share electrons (holding hands)
covalent
atoms transfer electrons (fist bump)
ionic
hydrogen bonds can only happen when
a covalent bond has already happened
attractions between a positively charged hydrogen and a weak, negatively charged atom (like oxygen)
hydrogen bond
how many electrons does the first energy level hold?
2
how many electrons do the outer energy levels hold?
8
an element is more reactive when…
it needs more electrons to become stable
used to measure acids and bases
pH scale
what determines acididity or how basic?
concentration of hydrogen ions
releases a hydrogen ion when dissolved in water?
acid
release hydroxide ions when dissolved in water
base
acids are proton _______
donors- H+ in solution
bases are proton ______
acceptors- OH- in solution
love water/ water soluble/ polar
hydrophillic
hate water/ lipid soluble/ non polar
hyrdrophobic
covalent bonds share ____________ becoming a molecule
valence electrons
power to attract electrons
electronegativity
electronegativity causes molecules to take on a __________
polarity
covalent bonds can be either…
polar or non polar
unequal sharing of electrons (partially charged atoms)
polar
equal sharing of electrons (no partial charge)
non polar
can polar and non polar mix?
NO
different number of electrons than protons
ions
more electrons than protons
anion
more protons than electrons
cation
electrostatic attraction between ions
ionic bond
anions attract ….
cations
2 polar covalently bonded molecules attracted by electronegativity
hydrogen bonding
holds water together
hydrogen bonding
homogeneous mixture of 2+ molecules, atoms, or ions
solution
same throughout whole mixture
homogeneous
compound dissolved in solution
solute
compound doing the dissolving
solvent
substance consisting of two or more different elements combined in a fixed ratio
compound
an element that is essential for life but required in extremely minute amounts
trace elements
breaking existing chemical bonds and forming new ones
chemical reactions
energy associated with the random movement of atoms and molecules
thermal energy
tendency of molecules of the same kind to stick together
cohesion
the clinging of one substance to another
adhesion
measure of how difficult it is to stretch or break the surface of a liquid
surface tension
Thermal energy in transfer from a warmer to a cooler body of matter
heat
measures the intensity of heat
temperature
substances that minimize changes in pH
buffers
