Chapter 11 Homework Physics 1310
A nucleon has the mass of
1 amu
Which contains more atoms?
1 kg of hydrogen
What is the molecular mass of a water molecule?
18 amu
How many protons should be added to the nuclei of oxygen atoms so the resulting gas will glow red when an electric current is in it?
2
How many shells are represented in the presently known periodic table?
7
How does a molecule differ from an atom? Give an example.
A molecule is composed of two or more atoms bonded together: H2O.
Who first explained Brownian motion and made a convincing case for the existence of atoms?
Albert Einstein
Why can't atoms be seen with a powerful optical microscope?
Atoms are much smaller than a wavelength of light.
What is a compound? Cite two examples.
Atoms of different elements with bonds between them: NaCl and H2O
What is a mixture? Cite two examples.
Atoms pressed together without bonding: air and salt and sand
What are the five most common elements in the universe?
C,H,O,N,Ca
What causes dust particles and tiny grains of soot to move with Brownian motion?
Collisions with invisible particles
How does one isotope differ from another?
Different number of neutrons
Since atoms are mostly empty space, why don't we fall through a floor we stand on?
Electrons in one atom repel the electrons in another.
Which of these atoms has the largest number of neutrons in the nucleus?
Gold (highest atomic number)
What is the evidence that dark matter exists?
Gravitational forces within galaxies are too great to be accounted for with ordinary matter.
Which of the following is an element?
Hydrogen
Where in the atom is most of its mass concentrated? What is this mass composed of?
In the nucleus as protons and neutrons
Who advanced the idea of atoms in the early 1800s?
John Dalton
What does the atomic number of an element tell you about the element?
The # of protons in its nucleus
Why aren't heavier elements much larger than lighter elements?
The larger positive charge in the nucleus pulls the electrons into closer orbits.
How does the approximate number of atoms in the air in your lungs compare with the number of breaths of air in Earth's atmosphere?
The numbers are the about the same, 10^23
Why can atoms be seen with an electron beam?
The wavelength of the electrons is smaller than an atom.
What occurs when a proton and an antiproton meet?
They annihilate each other
What is meant by the term nucleon?
a proton or a neutron
Which is NOT a compound?
air
A force that determines the chemical properties of an atom is
an electrical force
Nuclei of atoms that make up a newborn baby were manufactured in
ancient stars
The periodic table of the elements is a list of
atoms
A pair of helium nuclei fused together produces
berylium
Two protons removed from an oxygen nucleus result in
carbon
Heavy atoms are not appreciably larger in size than light atoms because the nuclei of heavy atoms have more
electrical charge
Which is the lightest particle?
electron
The chemical properties of matter are due mostly to their
electrons
The volume of matter is due mostly to its
electrons
Which of the following are negatively charged?
electrons
To become a negative ion, does an atom lose or gain an electron?
gain
The element gold contains
gold atoms
An isotope is simply an atom that
has different numbers of neutrons for the same element
A pair of hydrogen nuclei fused together produces
helium
One neutron added to a helium nucleus results in
helium
What element has the lightest atoms?
hydrogen
What is the most abundant element in the known universe?
hydrogen
How does the electric charge of a proton compare with the electric charge of an electron?
its equal and opposite
Which of these has the greatest number of protons in its nucleus?
lead
To become a positive ion, does an atom lose or gain an electron?
lose
A granite block is mostly empty space because the atoms in the granite are
mostly empty space between themselves
The charge in the nucleus of an antimatter hydrogen atoms is
negative
If a nitrogen atom and a slightly heavier oxygen atom have equal kinetic energies, which has the greater average speed?
nitrogen
If no molecules in a body could escape, would the body have any odor?
no
How are most of the elements with nuclei heavier than those of hydrogen and helium formed?
nuclear fusion in stars
mass number depends of the number of
nucleons in the nucleus
Although solid matter is mostly empty space, we don't fall through the floor because
of electrical forces
Are most of the atoms around us younger or older than the Sun?
older
The number of protons in a neutral atom is balanced by an equal number of
orbital electrons
Brownian Motion is caused by
particles larger than atoms bumping into them
Dark matter is considered to be
plentiful in the universe
An element is distinct because of its number of
protons
Atomic number refers to the number of
protons
Heavier atoms are not proportionally larger than lighter atoms due to the greater number of protons
pulling surrounding electrons into tighter shells.
Which is the smallest particle?
quark
Atoms can be photographed by
scanning electron microscopes AND electron beams
Assuming all the atoms exhaled by Julius Caesar in his last dying breath are still in the atmosphere, we breathe in at least one of them each
single breath
If we doubled the magnifying power of the most powerful optical microscope in the world, we would
still not be able to see or photograph an atom
Compared to the atoms that make up the body of an elderly person, the atoms that make up the body of a newborn baby are
the same age
Which of these statements is true?
there are only about 100 different kinds of atoms that combine to form all substances
Atoms heavier than helium were at one time manufactured by
thermonuclear fusion
The number of atoms in a common water molecule is
three
The difficulty of taking a photograph of an atom with light is
unwanted diffraction AND atoms are smaller than the wavelengths of light
Which of the following elements has the most mass?
uranium
Which of these atoms has the greatest amount of electrical charge in its nucleus?
uranium
Which of these atoms has the greatest number of electrons?
uranium
