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104 terms

Chemistry first semester exam

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18
How many groups are in the periodic table?
atomic mass
Mendeleev arranged the elements in his periodic table in order from increasing
metals
Which category of elements have the property of being malleable and ductile?
Mendeleev
The scientist credited with the first periodic table of elements was
7
How many periods are in the periodic table?
The periodic law
the relationship in which the physical and chemical properties of elements show a periodic pattern when the elements are arranged by increasing atomic number is called
groups
elements that have similar properties are aligned in vertical columns called
Iodine
which is the halogen that is in period 5?
Newlands
Which scientist characterized the law of octaves?
the chemical propertiesw of unknown elements and the existance of unknown elements
Mendeleev's periodic table was able to predict_____
metalloids (semimetals)
which category of elements is commonly used to make computer ships and solar cells due to their ability to conduct electricity only under certain conditions (semiconductors)
Dobereiner
Who classified metals into triads?
the energy change that occurs when an element gains an elecron
Electron affinity is
Mosely
Which scientist first arranged elements by atomic number?
true
TF
the max number of allowed valence electrons in any atom is 8
False
TF
The number of electrons in an orbital depends on the orbital's shape
true
TF
a quantum is a specific amount of energy
true
TF
an element can be identified by the characteristic bright-line atomic emission spectrum it can produce
false
TF
there are a total of three different types of d orbitals
Aufbau principal
electrons must be added one at a time to the lowest energy orbitals available according to the
distribution among orbitals
what info about electrons is given by the electron configuration?
in the ground state
when electrons are in their lowest energy orbitals available, the atom is
atomic orbitals
what is the region around the nucleus where electrons can be found called?
d
an f orbital can have how many orientations
occupy equal energy orbitals so that a maximum number of unpaird electrons result
Hand's rule states that electrons
in an excited state
when electrons are in a higher energy they are said to be
absorbes energy
When an electron jumps from a ground state to an excited state, it
2 electrons with the opposite spin
the Pauli exclusion principal states that each orbital in an atom can hold
position and velocity
the heisenberg uncertainty principle states that 2 things of an electron cannot be simultaneously measured
S
the _____ orbital is shaped like a sphere
in the outermost energy level.
Valence electrons are found
Rutherford
Which scientist described a positively charged core (nucleus) in the middle of a lot of empty space?
radium and polonium
Marie and Pierre Curie isolated which radioactive elements?
Chadwick
Which scientist described the existance of the neutron?
Atom
Which one is comprised of the other three? (proton, atom, electron, neutron)
electron
Which is the smallest part of an element that retains all the properties of the element?
silicon
Which element has 14 protons?
protons and neutrons
According to the modern concept of the atom, which are located in the nucleus of an atom.
Strong nuclear force
te force that holds protons together in the nucleus is called
0
what is the charge on a gama ray?
delta
which of the following are not produced by nuclear decay? alpha, beta, gama, delta
Democretus
who is the first to propose that matter is composed of tiny invisible particles?
anunequal number of protons and electrons
An ion always contain an
False
Tf
Aristotle named atoms atoms
False
tf
A cathode ray tube consists of a stream of protons
TRUE
tf
in a neutral atom the number of protons is equal to the number of electrons
True
TF
Gama rays emits energy but no particles
true
True
Nuclear decay can change one element into another element
False
TF
isotopes are forms of an elements that have the same number of protons but a different number of electrons
TRUe
TF
The atomic mass unit is based on the element Carbon-12
True
TF
A proton is a subatomic particle carrying a charge equal to but opposite of an electron
Electrical attraction between oppositely charged ions
The basis of an ionic bond is the
polyatomic ion
Ions that are formed from more than one atom is called
0
An ionic compound must have an overall charge of
high boiling points
Which is a property of substances that exhibit metallic bonding?
Chemical bond
which is described as the force holding two atoms together
High melting points
What is a physical propert of ionic compounds in their solid state?
The simplest whole number ratio of different atoms in a compound
An emperical formula always indicates
one atom
A monatomic ion consist of
noble gass
Elements tend to gain or lose electrons in order to acquire the electron confirguration of a
True
TF
Metallic elements tend to form cations rather than ions
tRuE
TF
A crystal lattice is a 3d structure formed by positive ions surrounded by negative ions surrounded by positive ions
false
TF
Because of the number of negative ions packed around each positive ion in a crystal lattice, ionic compounds are good conductors of electricity and heat in their solid state
FaLSe
TF
A single unit of an ionic compound is referred to as a molecule
false
TF
The oxidation number or charge of an ion ids always equal to the number of valence electrons it has
true
TF
An alloy results when an additional element is introduced into the metallic crystal
TRUE
A metallic bond is the attraction of a metallic cation for delocalized electrons
number of beats
A scientist designed a new drug to help slow the beating of the heart, and is interested in the beats of the heart with time. The scientist measures the beats of the heart every ten seconds. What is the dependent variable?
Clean up
What should you do when an experiment is finished?
protect your eyes
You should wear safety goggles to
it overlaps so many sciences.
Chemistry has been called the central science because...
color
Which is a qualitative measurement? color, mass, time, length
temperature
which is a quantitative measurement? hardness, color, taste, temperature
chem is try
The study of all substances and the changes they undergo is?
true
TF
A samples's color is a qualitative measurement
true
tf
If the distance covered by a car at constant speed for different intervals of time, then the distance is a dependant variable
f
tf
the goal of all experiments is to prove your hypothisis correct.
true
tf
when conducting an experiment, you should only manipulate one variable at a time
true
TF
The volume of a baloon increases as it is heated. The volume of the ballon is the dependant variable.
false
TF
if an accidental discovery is made, it means something went wrong with the experiment and the results should be discarted.
falso
TF
Mass is defined as anything that can be observed
false
tf
the best fit line connects all of the data points in a line graph
TRUE
TF
A control is part of the experiment that the other results will be compared to.
false
TF
in most line graphs, the dependant variable is placed along the X-axis
3420
How many meters are in 3.42 kilometers?
0.253
how many grams are in 25.3 centigrams?
g/cm
which is not an appropriate unit for measuring density? g/cm
g/ml
kg/l
g/l
6
how many significant digits are in 530,405,000
0 kelvin
Absolute zero reffers to
compound
A chemical composition of two or more different elements joined together in fixed proportions isk nowns as a
physical property
The density of silver is 10.5 g/cm3. Density is an example of a
chemical change
A piece of wood burning is an exaple of a
the mass of reactants is equal to the mass of products
According to the Law of conservation of mass, in any chemical change,
chromatography
a homogenious mixture can be seperated by what method?
Definitie proportions
The Law of _____ states that a compound is always composed of the same elemensts in the same proportion by mass
Distilation
what is the seperation technique that relies on the different boiling points of the parts of the mixture?
false
tf
the term gas and vapor can be used interchangeably
falso
tf
a change of state is a chemical change because ice and water do not resemble one another
true
matter that has uniform and unchanging composition is called a pure substance
falso
when a chemical change occurs, the product has greater mass than the reactants
true
mixtures can be seperated by a series of physical changes.
false
compounds can be seperated into their component elements by a series of physical changes.
false
An intensive physical property is one that depends on the amount of matter present
hetero
homo
homo
hetero
hetero
hetero
homo
homogenious or heterogenious.
1) Snickers candy bar
2) salt water
3) air
4) chocolate chip cookie
5) vegetable soup
6) dirt and rocks
7) Kool-Aid