chapter11 Flashcards
Are most of the atoms around us younger or older than the Sun?
most are older than the sun
Why can’t atoms be seen with a powerful optical microscope?
Atoms are much smaller than a wavelength of light
Why can atoms be seen with an electron beam?
The wavelength of the electrons is smaller than an atom
What are the five most common elements in humans?
C, H, O, N, CA
How are most of the elements with nuclei heavier than those of hydrogen and helium formed?
nuclear fusion in stars
What is the most abundant element in the known universe?
hydrogen
What element has the lightest atoms?
hydrogen
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.
How does the electric charge of a proton compare with the electric charge of an electron?
it is equal and opposite
What is meant by the term nucleon?
a proton or neutron
Where in the atom is most of its mass concentrated? What is this mass composed of?
in the nucleus as protons and neutrons
Which of the following are negatively charged?
electrons
What does the atomic number of an element tell you about the element?
the number of protons in its nucleus
How does one isotope differ from another?
has a different number of neutrons
Distinguish between mass number and atomic mass.
Mass number is the number of nucleons; atomic mass is the total mass of an atom
What is a mixture? Cite two examples
Atoms pressed together without bonding: air and salt and sand
Compared with the energy it takes to separate oxygen and hydrogen from water, how much energy is released when they recombine?
The same amount of energy is released when they recombine.
Which of these atoms has the largest number of neutrons in the nucleus?
gold
What is the evidence that dark matter exists?
Gravitational forces within galaxies are too great to be accounted for with ordinary matter.
What occurs when a proton and an antiproton meet?
They annihilate each other
Dark matter is considered to be __________.
plentiful in the universe
The charge in the nucleus of an antimatter hydrogen atoms is __________.
negative
The number of atoms in a common water molecule is __________.
three
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
A granite block is mostly empty space because the atoms in the granite are
mostly empty space themselves
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
Which of the following statements is true?
there are only about 100 different kinds of atoms that combine to form all substances
The difficulty of taking a photograph of an atom with light is
both of these
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.
Atoms heavier than helium were at one time manufactured by
thermonuclear fusion
Which of the following are electrically neutral?
neutrons
An element is distinct because of its number of
protons
Which is the smallest particle?
quark
Although solid matter is mostly empty space, we don’t fall through the floor because
of electrical forces
A force that determines the chemical properties of an atom is
electrical force
Atomic number refers to the number of
protons in the nucleus
The number of protons in a neutral atom is balanced by an equal number of
orbital electrons
Which of these has the greatest number of protons in its nucleus?
lead
Which of these atoms has the greatest number of electrons?
uranium
A pair of helium nuclei fused together produces
beryllium
The chemical properties of matter are due mostly to their
electrons
Compared to the mass of a hydrogen atom, the mass of an oxygen atom is
16x as great
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
Heavy atoms are not appreciably larger in size than light atoms because the nuclei of heavy atoms have more
electric charge
An isotope is simply an atom that
has different numbers of neutrons for the same element.
A nucleon has a mass of about
both are the same
Which of the following is NOT a compound?
air
Which of the following is NOT a mixture?
none
Which of the following statements is true?
molecules are the smallest subdivision of matter that still retain a substance’s chemical properties
When carbon and oxygen atoms combine, energy is
released by the reaction
How many atoms are in this carbohydrate molecule, C6H12O6?
24
If a gram of antimatter meets a kilogram of matter, the amount of mass to survive is
999 grams
If no molecules in a body could escape, would the body have any odor?
no
What element results if two protons and two neutrons are ejected from a radium nucleus?
radon
To become a negative ion, does an atom lose or gain an electron?
gains
To become a positive ion, does an atom lose or gain an electron?
loses
The electrical force is stronger between the nucleus and an inner electron for atoms of
high atomic number
Mass number refers to the number of
nucleons in the nucleus
What is the molecular mass of a water molecule?
18 amu
The mass of matter is due mostly to its
protons
The volume of matter is due mostly to its
electrons
Which of these atoms has the greatest amount of electrical charge in its nucleus?
uranium
What causes dust particles and tiny grains of soot to move with Brownian motion?
collisions with invisible molecules
Who first explained Brownian motion and made a convincing case for the existence of atoms?
albert einstein
Which of the following is an inert gas?
helium
How many different kinds of elements are in a water molecule?
two
