Chemistry Midterm Flashcards
What are the atomic number and the atomic mass of potassium?
Atomic #: 19
Atomic Mass: 39
Describe the location of metals, nonmetals, metalloids, and noble gases on the periodic table.
the metals are to the left of the line (except for hydrogen, which is a nonmetal), the nonmetals are to the right of the line, and the elements immediately adjacent to line are metalloids.
state four indicators of a chemical change.
change of color, production of an odor, change of temperature, evolution of a gas.
state two examples of a chemical change
iron rusting, wood burning.
what is a physical change?
a physical change is usually reversible change in the physical properties of a substance, as size or shape.
state two examples of physical change.
boiling water, crushing a can.
are most of the elements on the periodic table metals, metalloids, or nonmetals
most elements are metals.
what is chemistry
the branch of science that deals with the identification of the substances of which matter is composed.
what is the SI unit for Length?
Meter (m)
what is the SI unit for mass?
kilogram (kg)
what is the SI unit for time?
seconds (s)
what is the SI unit for volume?
cubic meters
what is the SI unit for number of particles?
mold
state two characteristics of halogens.
form acids when combined with hydrogen, fairly toxic
state two characteristics of noble gases.
colorless, odorless
state two characteristics of alkali metals
silver-like luster, high ductility.
state two characteristics of alkaline earth metals.
good conductors of electricity, low in ionization energy.
state two characteristics of Transition metals
good conductors of heat and electricity, can be hammered or bent into shape easily.
what is the formula for density?
P = m/v
state three characteristics of solids.
definite shape, definite volume, particles vibrate around fixed axes.
state three characteristics of liquids
definite volume, no definite shape, possesses only one free surface.
state three characteristics of gases.
easy to compress, expand to fill their containers, tends to flow.
heterogeneous mixture
one that does not have a uniform composition and in which the individual substances remain distinct.
homogeneous mixture
one that has uniform composition throughout and always has a single phase; also called a solution.
who wrote the atomic theory?
John Dalton
state the atomic theory.
all matter is composed of atoms.
state the Law of Multiple Proportions
states that when different compounds are formed by the combination of the same elements, different masses of one element combine with the same fixed mass of the other element in a ration of small whole numbers
state the Law of Conservation of Mass
states that mass is neither created nor destroyed during a chemical reaction but is conserved
state the Law of Definite Proportions
states that, regardless of the amount, a compound is always composed of the same elements in the same proportions by mass.
who conducted the gold foil experiment and what did it prove?
Rutherford’s gold foil experiment showed that the tom is mostly empty space with a tiny, dense, positively charged nucleus.
what experiment led to the discovery of the electron.
the cathode ray experiment
Describe Millikan’s experiment and what it proved.
Millikan could calculate the charge on the drop, the charges on the drops were all integer multiples of a fundamental unit of charge.
most of the mass of an atom is located in the
nucleus
most of the volume of the atoms created by the
free space
Hund’s rule
states that single electrons with the same spin must occupy each equal-energy orbital before additional electrons with opposite spins can occupy the same orbitals.
Aufbau’s Principle
states that each electron occupies the lowest energy orbital available
Pauli’s Exclusion Principle
states that maximum of two electrons can occupy a single atomic orbital but only if the electrons have opposite spins.
why does an electron go from its ground state to its excited state?
if it is given extra energy, such as if it absorbs a photon, or packet of light, or collides with a nearby atom or particle.
how many electrons can the first energy level hold?
2 electrons
how many electrons can the second energy level hold?
8 electrons
how many electrons can the third energy level hold?
32 electrons
ow did Mendeleev and Moseley organize the periodic table differently?
Mendeleev arranged elements ascendingly according to atomic masses, while Moseley` arranged them ascendingly according to atomic number.
what is the most electronegative element?
Fluorine
Which three elements are most likely to form a double or triple bond?
transition metals Ex: nitrogen
state three characteristics of ionic compounds.
have high melting points, hard and brittle, and dissociate into ions when dissolved in water.
