Exam 4 Physical Science
there are the same number of_______ in the nucleus as _______ surrounding the nucleus of an electrically neutral atom
Protons Elctrons
Which contributes more to an atom's mass: electrons or protons? Which contributes more to an atom's size?
Protons contribute more to an atom's mass while electrons contribute more to its size.
How many unpaired valence electrons are there in a nitrogen atom?
3
How many valence electrons does boron (B, atomic no. = 5) have?
3
What is the mass of one mole of H2?
2 g
How many bonds is nitrogen able to make?
3
Which of the following is a quantum number?
1
A nucleus with an atomic number of 10 and a mass number of 22 must have
10 protons. 12 neutrons. 22 nucleons.
What is the formula mass of a molecule of CO2?
44
How many atoms are in one molecule of Na2SO4?
7
The following statement describes which subatomic particle best? It is a nucleon.
A proton and a nuetron
How is the term photon related to the term quantum?
A quantum of light is actually one photon.
If you mix a typical aluminum ion (Al, atomic no. = 13) with a typical oxygen ion (O, atomic no. = 8), what compound is formed?
Al2O3
Which of these has the greatest energy per photon? Red, blue or green
Blue
Which element would have chemical properties the most similar to chlorine (Cl)?
Br
Phosphine is a covalent compound of phosphorus, P, and hydrogen, H. What is its chemical formula?
PH3
An atom loses an electron to another atom. Is this an example of a physical or a chemical change?
Chemical change involving the formation of positive ions.
Classify the following changes as physical or chemical: Wood burns to ashes; water begins to boil; grass grows; a rock is crushed to powder.
Chemical; Physical; Chemical; Physical
Which of the following elements are in the same period as magnesium (Mg)?
Cl
The hydrogen spectrum consists of many spectral lines. How can this simple element have so many lines?
One electron can be boosted to many different energy level
Which of the following statements about electrons is true?
Electrons are particles. Electrons have a negative charge Electrons in atoms can be excited by light energy Electrons behave like waves.
What was Niels Bohr's explanation for the observation of atomic spectra?
Electrons could only move in discrete energy steps within an atom
The amount of energy in a photon is directly proportional to the
Frequency of light
Which of the following molecules contains a polar bond?
H-F
Helium, He, is a nonmetallic gas and the second element in the periodic table. Rather than being placed adjacent to hydrogen, H, however, helium is placed on the far right of the table. Why?
Helium is most similar to other group 18 elements.
What it the main difference between an ionic and a covalent bond?
One is the sharing of a pair of electrons, the other is the transfer of at least one electron.
What is the valence shell?
It is the outermost shell of electrons in an atom
Magnesium ions carry a 2+ charge, and chloride ions carry a 1- charge. What is the chemical formula for the ionic compound magnesium chloride?
MgCl2
Two molecules, A and B, have very different physical properties. A and B do not mix. Molecule A boils at 80°C and freezes at -30°C. Molecule B boils at 35°C and freezes at -100°C. Which molecule is likely to have the largest dipole?
Molecule A
When nitrogen and fluorine combine to form a molecule, the most likely chemical formula is
NF3
Which of the following particles are electrically neutral
Neutron.
______ Accompany protons in the nucleus and have about the same mass as protons but are electrically neutral
Neutrons
Oxygen atoms are used to make water molecules. Does this mean that oxygen, O2, and water, H2O, have similar properties?
No, compounds are uniquely different from the elements from which they are made.
The phase in which atoms and molecules no longer move is the
Not gas or solid or liquid
Protons together with neutrons are called
Nucleons
Which bond is most polar?
O-H
Is chemistry the study of the submicroscopic, the microscopic, or the macroscopic, or all three?
Submicroscopic, because it deals with atoms and molecules, which can't be seen with a microscope. Microscopic, because it pertains to the formation of crystals Macroscopic, because it deals with powders, liquids, and gases that fill beakers and flasks.
How is Avogadro's number related to the numbers on the periodic table?
The atomic mass listed is the mass, in grams, of Avogadro's number's worth of atoms.
Since atoms are mostly empty space, why don't objects pass through one another?
The electrons on the atoms repel other electrons on other atoms when they get close.
What chemical change occurs when a wax candle burns?
The heated wax molecules combine with oxygen molecules.
Why are ion-dipole attractions stronger than dipole-dipole attractions?
The magnitude of the electric charge associated with an ion is much greater.
Why can't the elements of a compound be separated from one another by physical means?
Their atoms are too tightly bound to one another.
Which are older, the atoms in the body of an elderly person or those in the body of a baby?
They are of the same age, which is appreciably older than the solar system.
Which of the following might best explain the reason why electrons are restricted to certain energy levels in an atom?
They behave like restricted waves and are self-reinforcing.
Atoms of metallic elements can form ionic bonds, but they are not very good at forming covalent bonds. Why?
They have a great tendency to lose electrons
Atoms of metallic elements can form ionic bonds, but they are not very good at forming covalent bonds. Why?
They have a great tendency to lose electrons.
The frequencies of light emitted by an atom often add up to
a higher frequency of light emitted by the same atom. (This follows from two energy transitions in an atom summing to equal another energy transition)
Mass number =
Total nucleons (protons + neutrons in the nucleus)
Which of these photons has the greatest energy?
Ultraviolet.
In what sense can you truthfully say that you are a part of every person around you?
We are continually exchanging our atoms
Which has more atoms: a 1-gram sample of carbon-12 or a 1-gram sample of carbon-13?
a 1-gram sample of carbon-12
Which of the following statements best describes an element?
a material consisting of only one type of atom
A quantum of light is called a
a photon
The following statement describes which subatomic particle best? It has a relatively large mass.
a proton and a neutron
Which of the following is not a chemical change?
a rock being crushed to powder
Each spectral line in an atomic spectrum represents
a specific frequency of light emitted by an element.
The following statement describes which subatomic particle best?It is electrically charged.
an electron and a proton
Any material that is made up of only one type of atom is classified as
an element
Which of the following is the strongest form of interatomic attraction?
an ion-dipole interaction
What does the following element description actually mean? O
an oxygen atom with 6 protons and 12 neutrons
Which of the following describes the reason for the following application of metals?
are shiny are strong but can be bent
Is the following transformation representative of a physical change or a chemical change?
chemical change because the atoms are connected differently
A vertical column on the periodic table is called a
group
_____ define the volume of an atom
electrons
When an atom is excited, its
electrons are boosted to higher energy levels
Elements that are in the same ________ have a tendency to have very similar chemical properties due to periodic trends.
group
A hydrogen atom does not form more than one covalent bond because it
has only one electron to share.
Which of the following statements describes an isotope?
element with the same number of protons but a different number of neutrons
A hydrogen atom does not form more than one covalent bond, because it
has only one electron to share.
The most abundant element in the universe it
hydrogen
Where did the atoms that make up a newborn baby originate?
in the explosions of ancient stars
Which of these photons has the smallest energy? Infaered, ultraviolet, visable
infarred
When the atomic number doesn't match the number of electrons the atom is an
ion
Classify the following bond as ionic, covalent, or metallic (Na, atomic number 11; Cl, atomic number 17) Na with Cl Na with Na Cl with Cl
ionic, metallic, covalent
refers to atoms of the same element that contain the same number of protons but different numbers of neutrons in the nucleus
isotopes
Neon, Ne, (number 10) has a relatively large effective nuclear charge, yet it cannot attract any additional electrons because
its outermost shell is already filled to capacity.
The periodic table lists
more than 100 elements
What is known about atoms is that they are
mostly empty space.
The mass number of an element refers to the number of
nucleons in its nucleus.
A sample of iron weighs more after it rusts because
of the additional oxygen it contains
Which of the following best describes ionic bonding?
one atom giving up some of its electrons to another atom
The orbit of n=1 has
one wavelength, n=2 two and so on
When we speak of de Broglie waves, we're speaking of the wave nature of
particles.
A horizontal row on the periodic table is called a
period
What is known about atoms is that they are
perpetually moving. tinier than the wavelengths of visible light. recycling among innumerable forms.
Which of the following describes a nonmetal?
poor conductor of electricity
The atomic number is the number of _______ listed in each element on the periodic table
protons
The atomic number of an element matches the number of
protons in the nucleus of an atom.
Which has less energy per photon?
red light
The shell model of the atom views electrons as occupying
shells.
As to why electrons orbit in only certain orbits, a compelling explanation views electrons as
standing waves. Standing waves are stable and close in on themselves in phase.
What is the name of the following compound? SF3
sulfur trifluoride
The total number of nuetrons in an isotope is the mass number minus
the atomic number (protons)
The neon atom tends NOT to gain any additional electrons because
there is no more room available in its outermost occupied shell.
The symbol CO denotes
the combination of carbon and oxygen.
The origin of the elements is
the stars. A small portion of elements on Earth originated in the Sun. An even smaller portion are synthesized in laboratories. Most atoms beyond hydrogen, overwhelmingly, were manufactured in the stars. We really are made of stardust!
Electrons in the outermost shells of atoms are called
valence electrons.
What is the gas found within a bubble of boiling water?
water vapor
In the relationship E ~ f, E stands for energy, and f stands for
wave frequency, as defined for sound, radio, and light waves
