physical science chapter 12 hw
Which of the following is a property of light?
-It is a particle. -Its energy comes in packets of uniform size. -It is a wave. -*all of the above
Boron has primarily two isotopes, one with an atomic mass of 11 amu and another with an atomic mass of 10 amu. If the abundance of the boron atom with a mass of 11 amu is 18.9 percent and the abundance of the other isotope is 81.1 percent, what would be the average mass of the boron atom?
10.19 amu
If a neutral element has 8 neutrons and 7 electrons, which expression correctly identifies the element?
15 7N
The nucleus of an electrically neutral iron atom contains 26 protons. How many electrons does this iron atom have?
26
How many periods are there in the periodic table? How many groups?
7 periods and 18 groups
If a neutral element has the following chemical symbol, how many electrons does it have?235 92U
92
how might the spectrum of an atom appear if its electrons were not restricted to particular energy levels?
A broad spectrum of all colors would be observed.
What is the approximate mass of a carbon atom in atomic mass units (amu)? How about a carbon dioxide molecule?
A carbon atom has a mass of about 12 amu. Carbon dioxide would then have a mass of 44 amu.
What is the difference between a physical model and a conceptual model?
A physical model is a scale model; a conceptual model is a mental model.
An atom absorbs or emits only particular frequencies of light. White light bends into a glass prism and separates into a rainbow of colors. In which of these two scenarios does the electromagnetic radiation behave as a wave? As a particle?
Absorption of light shows particle behavior while bending of light shows wave behavior.
What causes an atom to emit light?
An atom emits light when an it is energized by heat or electricity.
Why do we say atomic spectra are like fingerprints of the elements?
An atom's spectrum has unique characteristic patterns.
Which has more potential energy: an electron close to an atomic nucleus or an electron far from an atomic nucleus?
An electron far from the nucleus has more potential energy.
Which of the following best explains what is happening when an atom emits light?
An electron is dropping from a higher to a lower energy level with the difference in energy between the two being emitted as light.
Distinguish between an atom and an element.
An element is made of only one type of atom.
What role does the atomic number play in the periodic table?
Atoms in the periodic table are ordered by increasing atomic number.
Which color of light comes from the higher energy transition, red or blue?
Blue is a higher frequency and therefore corresponds to a higher energy level transition.
The element bromine, BrBr (atomic number 35), has two major isotopes of similar abundance, both around 50%. The atomic mass of bromine is reported in the periodic table as 79.904 amu amu. Part A Choose the most likely set of mass numbers for these two bromine isotopes.
Br−79, Br−81
What was Niels Bohr's explanation for the observation of atomic spectra?
Electrons could only move in discrete energy steps within an atom.
Which of the following statements about electrons is true?
Electrons have a negative charge. Electrons in atoms can be excited by light energy. Electrons behave like waves. Electrons are particles.
What is the main tenet of Plank's quantum hypothesis?
Energy comes in discrete packets of a certain minimum size.
Which element has the atomic number 9?
F
Which is the oldest element?
Hydrogen
How is it possible to deduce the identity of an element from its electron configuration?
If the atom is electrically neutral, the number of electrons corresponds to the atom's atomic number.
Where did the atoms that make up a newborn baby originate?
In the explosions of ancient stars.
Which of the following does not describe a neutron?
It has a positive charge equivalent but opposite of an electron's
Which of the following statements does not describe a proton?
It orbits around the nucleus of an atom.
What does a spectroscope do to the light coming from an atom?
It separates the colors emitted by an atom
How can a hydrogen atom, which has only one electron, have so many spectral lines?
One electron can be boosted to many different energy levels.
Which atom is largest?
Rb
If you remove two protons and two electrons from a sulfur atom (S), what new element is formed?
Si
If you place a Styrofoam cup on the table and a bunch of BBs move around it randomly, what will happen to the cup, and why?
The cup will move randomly in different directions because the BBs will exert unequal forces on the cup in different directions
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.
Why isn't dirt listed in the periodic table?
The periodic table lists only elements made of one kind of material. Dirt is a mixture of elements and compounds.
What happens to the properties of elements across any period of the periodic table?
The properties of elements gradually change across any period of the periodic table.
How do we account for the great variety of substances in the world?
There are many possible combinations of atoms.
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.
List several common transition metals.
Tungsten, platinum, and iron
Why can't we see atoms?
We see with light energy and the wavelength is larger than the object and so it is not reflected.
What does the following element description actually mean?hydrogen-2
a hydrogen with one neutron and one proton
The following statement describes which subatomic particle best?It is a nucleon.
a proton and a neutron
What does the following element description actually mean?23892U
a uranium atom with 92 protons and 146 neutrons
The following statement describes which subatomic particle best?It is located outside of the nucleus.
an electron
Which of the following elements is a gas at room temperature?
argon (Ar)
If an element has 18 protons and 20 neutrons and 18 electrons, which expression correctly identifies the element?
argon-38
Isotopes are identified by their
atomic mass number
If an atom has 43 electrons, 56 neutrons, and 43 protons, what is its approximate atomic mass? What is the name of this element?
atomic mass, 99 amu; Technetium
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 and two neutrons are removed from the nucleus of an oxygen atom, a nucleus of which element remains?
carbon-12
Which of the following elements is in the fourth period?
chromium (Cr)
Which of these properties describes a metal?
conducts heat very well
An element is best described as a material
consisting of only one type of atom.
Which contributes more to an atom's size?
electron
Which electrons are most responsible for the properties of an atom?
electrons in the outermost shell
The elements fluorine, chlorine, and bromine are also known as _______.
halogens
The atoms that make your body _______.
have existed since the start of the universe
Strontium, Sr (number 38), is especially dangerous to humans because it tends to accumulate in calcium-dependent bone marrow tissues (calcium, Ca, number 20). This fact relates to the organization of the periodic table in that strontium and calcium are both
in group 2 of the periodic table
Are most elements metallic, nonmetallic, metalloid, or not yet confirmed?
metallic
The following statement describes which subatomic particle best? It does not have an electrical charge.
neutron
What is at the center of every atom?
nucleus
How many electrons are there in the third shell of sodium, Na (atomic number 11)?
one
How many types of atoms can you expect to find in a pure sample of any element?
one
A unit of light is the
photon
Which of the following describes a nonmetal?
poor conductor of electricity
Which contributes more to an atom's mass: electrons or protons?
proton
The following statement describes which subatomic particle best?It is electrically charged.
proton and electron
The following statement describes which subatomic particle best?It has a relatively large mass.
proton and neutron
What did Robert Brown see under the microscope?
specks of dust moving around
Using the following generic atom description, choose the correct method for determining the number of neutrons.FGX
subtract G from F
Which chemical family is composed almost entirely of man-made elements?
the actinides
hen we breathe, we inhale oxygen, O2, and exhale carbon dioxide, CO2, plus water vapor, H2O. Which likely has more mass: the air we inhale or the same volume of air we exhale?
the air we exhale
Why did the particles jiggle around?
the particles were struck by atoms, but unequally on different sides.
Oxygen, O, (number 8), sulfur, S, (number 16), and selenium, Se, (number 34) have such similar chemical properties because
their outermost shells contain the same number of electrons.
Does breathing cause you to lose or gain weight?
to lose weight
