atomic radius
half the distance between 2 nuclei of 2 identical atoms that are bonded together
as you move down a group in the periodic table, the atomic radius _______? why?
increases; valence electrons are in the higher energy levels (farther away), therefore, not as strongly attracted to the nucleus, inner electron shield valence electrons from the median pull(blocking)
as you move across a period in the periodic table, the atomic radius _______? why?
decreases; effective nuclear charge increases as we go across a period, so electrons are strongly attracted to the nucleus
a cation is _______ than the corresponding neural atom. why?
smaller; the same nuclear (#p+) can pull fewer amount of electrons more effectively toward the nucleus > smaller size.
an anion is _______ than the corresponding neutral atom. why?
larger; an anion has the same charge but increased # of electrons so its harder to pull close to the nucleus (electron repulsion = larger size)
ionization energy
opposite of atomic radius; energy needed to remove an electron from a gaseous atom
as you move down a group in the periodic table, the ionization energy _______. why?
decreases; because the size of the atom increases and the valence electrons are further away form the nucleus and are easier to remove
as you move across and period in the periodic table, the ionization energy _______. why?
increases; atoms get smaller across and period and electrons are strongly attracted to the nucleus and therefore are harder to remove > more energy is needed
chemical bond
the force that holds two atoms together and makes them function as a single unit
bond energy
the energy needed to break a bond, its magnitude determines the strength of the bond
ionic bonds
metals + nonmetals
ionic bonds are formed by _______ .
electrons transferred from metals to nonmetals
covalent bonds (polar and nonpolar)
2 or more nonmetals
covalent bonds are formed by _______ .
electrons shared (equal - polar; unequal - nonpolar)
metallic bonds
metal cation and electrons
metallic bonds are formed by _______ .
shared electrons
metals tend to form _______ and nonmetals usually form ________.
cations, anions
octet rule
stable "noble" gas configurations are achieved when atoms gain/lose electrons to have EIGHT valence electrons
molecule
group of atoms acting together (bonds) representing the smallest unit that participates in a chemical reaction
molecular formula
true formula for a molecule, represents # and types of atoms that are bonded together
_______ ________ are a type of structural formula and show which atoms are bonded to which other atoms in a molecule and how many electrons they share
lewis structures
lone pair (unshared pairs) of electrons
electrons that are not bonded (1 or 2 dots)
double bond
in order to achieve on octet, sometimes atoms have to share 2 electrons
triple bond
in order to achieve on octet, sometimes atoms have to share 3 electrons
exception to the octet rule: hydrogen and beryllium
only need 2 electrons and 4 electrons (H - 2, Be - 4)
exception to the octet rule: boron and aluminum
only need 6 valence electrons
exception to the octet rule: phosphorous and sulfur
can have 8, 10, or 12 valence electrons
mono
1
di
2
tri
3
tetra
4
penta
5
hexa
6
hepta
7
octo
8
nona
9
deca
10
chemistry
study of matter and the changes it undergoes
matter
anything that has mass and takes up space
states of matter
solids, liquids, and gases
solid
definite shape, definite volume
liquid
indefinite shape, definite volume
gas
indefinite shape, indefinite volume
physical properties
characteristics that can be observed without altering the identity or composition of the substance
chemical properties
characteristics that can only be observed by changing the identity or composition of the substance
physical change
does not change the composition or identity of the substance
chemical change
does change the composition or identity of the substance
law of conservation of matter
matter is neither created nor destroyed; mass of the substances before the reaction = mass of the substance after the reaction
element
substances that cannot be broken down into any other substances
periodic table
a table which organizes the elements according to their chemical properties
compound
2 or more elements chemically conbined
pure substances
refers to elements and compounds; always has the same composition
mixture
combination of pure substances; had variable composition; these can be separated by physical changes
heterogenous mixtures
regions of the mixture are different(composition is not uniform; different parts can be distinguished)
homogenous mixtures
mixture is the same throughout (different parts cannot be distinguished)
filteration
separate solids from liquids (ex. tea bags)
distillation
separate liquids based on boiling point
crystillization
separate pure solids from impurities (rock candy)
chromatography
separate parts of a homogenous mixture (ink)
precision
how close 2 or more values are to each other
accuracy
how close a measured value is to the known value
density
mass/volume
absolute zero
the temperature at which all motion ceases; zero on the Kelvin scale (no negative temp for Kelvin possible)
Kelvin
°C + 273
energy
the ability to do work or produce heat
heat
the flow of energy between objects at different temperatrures
1 cal
4.184 J
4.184 J
1 cal
1 kcal & 1 Cal
1000 cal
temperature
a measure of the random motions in a substance
exothermic
a process that releases heat to the surroundings
endothermic
a process that absorbs heat from its surroundings
specific heat capacity
the amount of heat required to raise the temperature of 1 gram of a substance by 1°C
specific heat formula
Q = m x c x ΔT
calorie
the amount of heat required to raise the temperature of 1 gram of water by 1°C
percent error formula
((∣experimental - theoretical)/theoretical) x 100
atom
most basic fundamental unit of which elements are made of; smallest particle that retains the properties of the elements
nucleus
small, dense, + charged; contains protons + neutrons
protons
positively charged; relative mass of 1; relative charge of 1
electrons
negatively charged; relative mass of 1; relative charge of -1
cation
charged; formed by atoms losing electrons
anion
charged; formed by atoms gaining electrons
balancing equations
the equalization of ions on the reactants side of an equation and the products on the other side of the equation
diatomics
H N F O I Cl Br
synthesis
A + B → AB
decomposition
AB → A + B
single replacement
A + BX → AX + B
double replacement
AX + BY → AY + BX
combustion
CXHY + O2 → CO2 + H2O
metal carbonate
metal oxide + CO2 → decompostion
metal chlorate
chop off excess O2 → decomposition
atomic mass
the mass of one atom of that unit (amu → atomic mass units)
formula mass
sum of the average atomic masses of each atom in a chemical formula
mole
SI base unit that measures an amount of matter. -6.022 × 10²³ (avogadro's #) particles (atoms, ions, formula units, molecules)
molar mass
mass in g of 1 mol of a substance containing 6.022 × 10²³ representative particles.
empirical formula
simplest formula containing the lowest whole # ratio of atoms present; may or may not be a true formula; all formulas are empirical
percent compostion
(part/whole) x 100
molecular formula
true formula for molecule; whole # molecule of empirical formula
molecular formula formula
molar mass of the molecule/empirical mass
stoichiometry
study of quantitative relationships between the amount of reactants by using a balanced equation