Module 4

The half-life of an isotope is one day. At the end of two days the amount that remains is

1/4

The half-life on an isotope is one day. At the end of three days, how much of the isotope remains?

1/8

How many electrons are in the outermost shell of strontium (Sr, atomic number 38)?

2

How many shells are completely filled for the chlorine ion, Cl1- (Cl, atomic #17)?

3

Suppose that a certain atom possesses only four distinct energy levels. Assuming that all transitions between levels are possible, how many spectral lines will this atom exhibit?

6

When radium (A = 88) emits an alpha particle, the resulting nucleus has atomic number

86

Humidity is a measure of the amount of water vapor in the atmosphere. Why is humidity always very low inside your kitchen freezer?

At the cold temperatures of your kitchen freezer, water molecules in the vapor phase are moving relatively slowly, which makes it easier for them to stick to inner surfaces within the freezer or to other water molecules.

Why is it not possible for the STM to make images of the inside of an atom? -The most representative "image" of the inside of the atom would be a picture of empty space. -The STM ultrathin needle itself is made of atoms and so is not tiny enough to pierce through an atom much like a sewing needle can pierce into a ping pong ball. -The STM works by passing a current across a tiny gap between the tip of an ultrathin needle and the surface being studied. No gap, no image. -All of the above are reasonable answers.

all of the above

An atom with an imbalance of electrons to protons is

an ion

You could swallow a capsule of germanium, Ge (atomic number 32), without significant ill effects. If a proton were added to each germanium nucleus, however, you would not want to swallow the capsule because the germanium would

become Arsenic

If two protons are removed from an oxygen nucleus, the result is

carbon

The number of elements in a period is

equal to the electron capacity of the shells.

All deposits of natural uranium contain appreciable amounts of

lead

The reason a granite block is mostly empty space is because the atoms in the granite are

mostly empty space themselves.

When a gamma ray is emitted by a nucleus, the nucleus then has appreciably less: charge. mass. both of these neither of these

neither of these

When two different elements combine to form a compound the resulting properties of the compound are

not necessarily anything like those of the elements.

A solid is not considered fluid because

of the fixed arrangement of its atoms or molecules.

Carbon dating requires that the object being tested contains

organic material

The atomic number of an element is the same as the number of its

protons

Electric forces within an atomic nucleus tend to

push it apart

If we doubled the magnifying power of the most powerful optical microscope in the world, we would

still not be able to see an atom.

Which will leak more neutrons, two separate lumps of uranium or the same two lumps stuck together?

two separate lumps

The mass of an atomic nucleon is nearly

two thousand times the mass of an electron.

Which of the following shows elements in order of increasing atomic size (Cl, atomic #17; K, atomic #19; Br, atomic #35; Rb, atomic #37)?

Cl < Br < K < Rb

The volume of matter comes mostly from its

Electrons

If one neutron is added to a helium nucleus, the result is

Helium

The most abundant element in the universe is

Hydrogen

Which of these statements is true? A molecule is the smallest particle that exists. Chemical elements are made up of about 100 distinct molecules. Molecules form atoms that in turn determine chemical properties of a substance. None of these statements are true.

Molecules are the smallest subdivision of matter that still retain chemical properties of a substance.

In an electrically neutral atom, the number of protons in the nucleus is balanced by an equal number of

Orbital electrons

Why is the process of science not restricted to any one particular method?

The scientist needs to be open to all possibilities and different ways of doing science in order to gain as much knowledge as possible from his or her research.

How does the wave model of electrons orbiting the nucleus account for the fact that the electrons can have only discrete energy values?

When an electron wave is confined, it is reinforced only at particular frequencies.

Which has more atoms: a 1-gram sample of carbon-12 or a 1-gram sample of carbon-13?

a one gram sample of carbon-12

Of the three sciences: physics, chemistry, and biology the most complex is

biology because it is based upon both the laws of chemistry and physics.

When a nucleus emits a beta particle, its atomic number

changes, but its mass number remains constant.

When a beta particle is ejected from a nucleus, the nucleus then has a greater

charge

Classify the following changes as physical or chemical. Even if you are incorrect in your assessment, you should be able to defend why you chose as you did. Wood burns to ashes; water begins to boil; grass grows; a rock is crushed to powder.

chemical; physical; chemical; physical

Carbon-14 is produced in the atmosphere principally by

cosmic ray bombardment

The origin of cosmic rays is the

cosmos

Detonation of a fusion type hydrogen bomb is started by

igniting a small fission bomb.

Generally speaking, the larger a nucleus is, the greater its

instability

In both fission and fusion, mass

is changed ti kinetic energy

Compared to the mass of a uranium nucleus before splitting, the pieces it splits into have

less mass

Would you use a physical model or a conceptual model to describe the following: the brain; the mind; the solar system; the beginning of the universe?

physical; conceptual; physical; conceptual

Most of the radioactivity we personally encounter comes from

the natural enviroment

What makes an element distinct?

the number of protons