Chemistry PPT Flashcards
has mass; occupies space; all living things are made up of it
matter
the smallest particle of a substance that still retains its chemical properties
atom
List the 4 elements of atom structure.
atomic nucleus, protons, neutrons, and electrons
contains two subatomic particles
atomic nucleus
List the 2 subatomic particles that make up the nucleus.
protons and neutrons
subatomic particles that carry a positive charge
protons
subatomic particles that are uncharged
neutrons
negatively charged; move around the nucleus
electrons
What’s the ratio of electrons to protons in each atom?
1:1
same amount of each
number of protons; unique to each atom
atomic number
number of protons and neutrons combined
atomic mass
atoms with the same number of protons; have the same chemical properties
elements
How many known elements are there?
117
atoms with the same number of protons but a different number of neutrons; results in different mass numbers; defined by writing in superscript; does not alter the chemical behavior of an atom
isotope
isotopes that have significantly different numbers of neutrons as compared to protons; unstable; breakdown over time
radioactive isotopes
when radioactive isotopes breakdown over time and energy is released; occurs at a constant rate
radioactive decay
substance with a radioactive isotope attached to it
tracer
List 3 uses of radioactive isotopes.
can insert into the body,
can detect the energy emitted,
useful in other areas of biology
example of a biological use of radioactive isotopes; forms images of body tissue
PET scan
Positron-Emission Tomography
What determines if two atoms interact?
- Molecular Motion
2. Arrangement and Amount of Electrons
molecules in constant motion (speed depends on temp.); reactions occur due to random collisions
molecular motion
List what the chance of molecular collision is based on.
the density and speed of the molecules
interact with different atoms because they are the furthest out; attracted to the positive nucleus; posses energy; move in orbitals
electrons
volume of space that surrounds the nucleus where an electron is most likely to be found
orbital
Each orbital holds a maximum of ___ electrons.
2
Orbitals closest to the nucleus are ___ in energy.
lower
Atoms with full orbitals are ___ stable.
most
If there is an empty space in an atom’s orbital, what can happen to that atom?
It can interact with another atom.
What are the different shaped orbitals?
S, P, and D orbitals
spherical orbital
S orbital
dumbbell-shaped orbital
P orbital
pear-shaped orbital
D orbital
Rather than grouping orbitals by shape, what is an easier method?
grouping into energy levels (shells)
a simple way to show how electrons are placed within an atom
shell model
shell with the lowest energy; 1 orbital; can hold 2 electrons
1st shell
shell with 4 orbitals; can hold up to 8 electrons
2nd shell
Atoms with incomplete outer electron shells are ___ reactive.
more
What are the 3 ways to fill the outermost shell?
gain, lose, or share electrons
atoms with a full outermost shell
nonreactive atoms
another name for a nonreactive atom
inert
examples of nonreactive atoms
Helium, Neon, Argon
group of atoms held together by energy
molecule
the force that holds the atoms in a molecule together
chemical bond
What are the 3 types of chemical bonds?
ionic, covalent (strongest), and hydrogen (weakest)
type of bond formed when electrons are gained and lost between two atoms
ionic bond
form as a result of ionic bonds
ions
atoms that have lost or gained 1/more electrons; number of protons differs from the number of electrons; have an electric charge (+ / -)
ions
atom that has lost electrons (electron donor); has a positive charge; has more protons than electrons
cation
atom that has gained electrons (electron acceptor); has a negative charge; has more electrons than protons
anion
measure of an atom’s ability to pull electrons from other atoms; depends on atom’s size and number of vacancies
electronegativity
In an ionic bond, a ___ electronegative atom will pull an electron from another atom with ___ electronegativity.
highly,
lower
type of bond that shares a pair of electrons between two atoms; forms between 2 atoms of similar electronegativity
covalent bonds
Biologically, covalent bonds are formed by which elements?
O, C, P, and N
covalent bond in which 1 pair of electrons is shared
single covalent bond
covalent bond in which 2 pairs of electrons are shared
double covalent bond
covalent bond in which 3 pairs of electrons are shared
triple covalent bond
What molecules come from the 4 covalent bonds formed by Carbon atoms?
ethanol, ethylene, acetylene, and caffeine
type of covalent bond in which two identical atoms share electrons equally; atoms have identical electronegativities; nuclei of the atoms have the same number of protons
nonpolar covalent bonds
type of covalent bond that occurs between atoms of different elements; no net charge on molecule (has a positive and negative end/poles)
polar covalent bonds
In a polar covalent bond, electrons spend more time near the nucleus with more ___, giving it a slightly ___ partial charge.
protons,
negative
In a polar covalent bond, the element with fewer protons has a slightly ___ partial charge.
positive
example of a polar covalent bond
H₂O
example of a nonpolar covalent bond
O₂
attraction between a hydrogen atom and an electronegative atom; both involved in separate polar covalent bonds
hydrogen bonds
Water molecules attract each other and hydrogen bond. Due to partial charges, this results in ___.
lattice
biological significance of water’s temperature property
buffer: resists temperature changes in aquatic ecosystems and in body cells
List the properties of water.
temperature, evaporation, ice, cohesion, adhesion, reactions, solvent
biological significance of water’s evaporation property
sweating in mammals
Ice is ___ dense than liquid water.
less
biological significance of water’s ice property
insulation for ponds and streams
the attraction between two polar water molecules
cohesion
biological significance of water’s cohesion property
creates surface tension on ponds
the attraction between water and another polar molecule
adhesion
biological significance of water’s adhesion property
allows water to carry nutrients through plants
property of water in which water attracts and repels other polar molecules
reaction
when water attracts other polar molecules it’s called
hydrophilic (water loving)
when water repels nonpolar molecules it’s called
hydrophobic (water hating)
example of a hydrophilic reaction with water
sugar
example of a hydrophobic reaction with water
oil
property of water in which ions and polar molecules dissolve easily in water
solvent
in water’s solvent property, water molecules cluster around molecules forming what
hydration layers
process of spontaneous ion formation
ionization
covalent bonds in water can spontaneously break resulting in what
positively charged hydrogen ion (H+) and negatively charged hydroxide ion (OH-)
substance that increases the concentration of H+ when dissolved in water; pH below 7
acid
Stronger ___ produce more H+ and have a ___ pH.
acids,
lower
a substance that combines with H+ when dissolved in water; lowers the H+ concentration; pH above 7
base
Stronger ___ combine with more H+.
bases
What is the pH of a cell?
close to 7
Cell chemical reactions constantly produce what?
acids and bases
substance that can take up or release H+ in solution as the H+ concentration changes; pair of substances (1 acid and 1 base) that interact in reversible reactions
chemical buffer
buffer example
human blood
What happens with the chemical buffer when blood pH rises?
carbonic acid dissociates to form bicarbonate and H+
What happens with the chemical buffer when blood pH drops?
bicarbonate binds H+ to form carbonic acid
