Download Questions About Atoms and Elements

Questions About Atoms and Elements
Chemistry
1.) The following statements are about the particles that make up the atom. For
each statement write:
p if it describes the proton
e if it describes the electron
n if it describes the neutron
a.) The positively-charged particle ______
b.) Found with the proton, in the nucleus ______
c.) The particle that can occur in different numbers in atoms of the same
element ______
d.) Held in shells around the nucleus. ______
e.) The negatively-charged particle. ______
f.) The particle with the negligible mass. ______
g.) The number of these particles is found by subtracting the proton number
from the nucleon (mass) number. ______
h.) The particle with no charge. ______
i.) The particle with the same mass as a neutron. ______
j.) The particle that dictates the position of the element in the Periodic Table.
______
2.) The atoms of an element can be represented by a set of three letters, as shown
below.
y
zQ
a.) What do the following letters stand for?
i.) Q _____________________
ii.) y _____________________
iii.) z ____________________
b.) How many neutrons and protons are there in these atoms?
i.)
ii.)
107
47
Ag
Neutrons _______ Protons ________
63
29
Cu
Neutrons _______ Protons ________
iii.)
1
1
iv.)
20
10
v.)
238
92
H
Ne
U
Neutrons _______ Protons ________
Neutrons _______ Protons ________
Neutrons _______ Protons ________
c.) Most Bromine atoms have 45 neutrons. Describe a bromine atom, using
the method in b.).
_____
_____
____
3.) For each of the six elements aluminum (Al), boron (B), nitrogen (N), oxygen
(O), phosphorus (P), and sulfur (S) fill in the table below:
Element
Period in
Periodic
Table
Group
Number in
Periodic
Table
Proton
(Atomic)
Number
Number of
Number of
electrons
Electronic
Outer
in neutral configuration
Shell
atom
electrons
Al
______
______
______
______
________
______
B
______
______
______
______
________
______
N
______
______
______
______
________
______
O
______
______
______
______
________
______
P
______
______
______
______
________
______
S
______
______
______
______
________
______
4.) Strontium, proton (atomic) number 38, is in the fifth period of the Periodic
Table. It belongs to Group II. Complete the following.
A neutral atom of strontium has:
a.) how many electrons? ________________
b.) how many shells of electrons? _____________
c.) How many electrons in its outer shell? __________
5.) Boron has two types of atoms, shown below.
Proton
Neutron
Electron
Atom A
Atom B
a.) What is different about these 2 atoms?
b.) What name is given to atoms like these?
c.) Describe each atom in shorthand form, as in problem 3.).
_____
_____
____
_____
_____
____
d.) What is the nucleon (mass) number of atom A? ________
e.) Is Atom B heavier, or lighter, than Atom A? _________________
f.) Give the electron configuration for:
Atom A _______________
Atom B _______________
g.) Do two isotopes of the same element have the same electron
configuration? ________
6.) The two metals sodium (proton (atomic) number 11) and magnesium (proton
(atomic) number 12) are found next to each other in the Periodic Table.
a.) State whether each phrase is the same, or different, for their atoms:
i.) The number of electron shells. _________________
ii.) The number of outer (valent) electrons _____________
The relative atomic mass of sodium is 23.0.
The relative atomic mass of magnesium is 24.3.
b.) Which of the two elements may exist naturally as a single isotope? Justify
your answer.
7.) This diagram represents the electronic arrangement for a neutral atom of an
element.
a.) Give the electron distribution for the atom. _______________
b.) What is special about this arrangement? ___________________________
c.) Which group of the Periodic Table does the element belong to? ________
d.) Name the element. ____________________
e.) Name another element with the same number of outer-shell electrons in its
atoms. _______________________________
8.) Gallium exists naturally as a mixture of two nonradioactive isotopes,
gallium-69 and gallium-71. The proton (atomic ) number of gallium is 31.
a.) i.) How many neutrons are there in gallium-69? ___________
ii.) How many neutrons are there in gallium-71? __________
Gallium also has a radioactive isotope, gallium-67. As gallium-67 decays, it
gives out rays called gamma rays.
b.) How does the radioactive isotope differ from the non-radioactive isotope?
_______________________________________________________
c.) Name two possible uses, one medical and one non-medical, for gallium-67.
_______________________________________________________
_______________________________________________________
9.) From the following list of names:
Aristotle
Niels Bohr
Boyle
Chadwick
Marie Currie
John Dalton Democritus
Proust
Rutherford
J. J. Thomson
Identify the person most associated with each statement below. Some names
will be used more than once.
a.) ____________ Gold Foil Experiment
b.) ____________ Concept of electron shells
c.) ____________ Analyzed compression of gases, concluding that empty
space predominated the volume.
d.) ____________ In noticing the ratios of elements are always constant for a
given compound, concluded elements must be composed
of small, indivisible particles he called atoms.
e.) ____________ Ancient Greek who proposed that matter can be broken
down an infinite number of times and still maintain its
properties.
f.) _____________ Electrons exist in an atom.
g.) ____________ Ancient Greek who proposed things are made of discrete
units called atomos.
h.) ____________ Cathode ray tube.
i.) ____________ Atom composed of a nucleus containing positive charge.
j.) _____________ Neutrons are also present in the nucleus of an atom.
k.) ______________ Plum pudding model of an atom.
l.) _______________ Investigated finding medical uses for radiation.
m.) _______________ Recognized alpha particles, beta particles, and gamma
rays.
n.) ______________ Discovered elements polonium (Po) and radium (Ra).
CHALLENGE PROBLEM
10.) In this problem we will estimate how likely it is that an alpha particle will
strike the nucleus of a gold atom when passing through Rutherford’s gold foil,
which was 0.00004 cm thick (4. x 10-7 m thick)
We have mentioned that a typical atom has a radius of approximately 1 x 10-10
m. We will assume that a typical nucleus is about 1 x 10 -14 m (some references
give a value of about 1 x 10-15 m, but in this problem let’s use 1 x 10-14 m).
Gold atoms are arranged in a face centered cubic FCC arrangement, as shown
in the diagram below:
s
r
a.) What is the length of the diagonal of a face (in terms of r and in meters)?
b.) What is the length, s, of a side of a face in meters? (show calculations)
c.) What is the area of a face of the cube (in square meters)?
d.) The cross section of how many nuclei are included on a face?
s
r
e.) What is the total cross sectional area of the nuclei on the face?
f.) What percent (as a decimal) of the face is a nucleus?
g.) What is the reciprocal of part f.)? This gives how many alpha particles
would pass through for every alpha particle that hits a nucleus.
h.) How many atoms would line up over a thickness of 4.0 x 10-7 m?
i.) Divide your answer in part g.) by that in part h.). This gives approximately
how many alpha particles would pass through for every 1 that is deflected
by a collision with a nucleus.