3. The effective nuclear charge is
a. equal to the suns of the charges of the protons in
b. equal to the suns of the charges of the protons in
the nucleus minus the sum of the electrons in the
c. lest than tire sum of the charges of the protons in
the nucleus due to shielding by the electrons in the
d. lest than the sum of the charges of the protons in
tire nucleus due to nisielding by the electrons in the
lower, filled shells
a. greater than the suns of the charges on the protons
in the nucleus
4. isotopes are
a. atonts with the same nutotber of neutrons but
different nuntbers of protons
b. atoms seitls the same number of protons but
different numbers of neutrons
c. atoms witls tire same sum of neutrons plus protons
but different numbers of neutrons and of protons
d. atoms with the same number of protons and
e. atoms seith the tame number of neutrons and
5. Radioisotopes are umrstable because
a. there Is an equal number of protons and neutrons
in the nucleus
b. rite attractive nuclear forces anmong the neatrons
and protons are too small to balance the repulsive
forces ansong tire protons
c. tire number of neutrons is greater than the riuumber
2. What is the maximum nunaber of electrons allowed
In the tirird electron shell of an atom?
Select the letter of the best atoner below.
1 Which of the following is the correct Lewis diagram
Knowledge and Understanding
Chapter 1 Elements and the Penindic Table. MHR 45
Lewis diagrams. Drase rhe correct Lewis diagram for
9. Explain what is incorrect about each of the folloss’ing
d. the attractive forces among the protons are less than
the repulsive forces among the neutrons
a. the repulsive forces among the electrons are greater
than the repulsive forces among the protons
6. WhIch statement about the size of the atomic radius is
a. Tin atomic radius decreases going down a group.
b. Ile atomic radius increases going across a period
from left to right.
C. Tie atonric radius Is unrelated to its position in the
d. Tie atomic radius increases going up a group.
a. Tie atomic radius decreases going across a period
from left ro right.
7. Which statement about Ionization energy Is true?
a. The first ionization energy is greater tItan the
second, third, or fourth ionization energy.
b. ‘tIe Ionization energy is the same for atoms of all
elements in the sante group.
C. For elements in a given period, the ionization
energy is greatest for atouts of the elensent with
a filled outer electron shell.
d. tonization energy decreases going across a group
from left to right.
a. Tie Ionization energy Is greatest for atoms of
elements that have ois one electron in the
valence shell of their atoms.
8. WhIch statement about electronegativity is true?
a. Electronegativiry Is the energy change that occurs
when an electron is added to an atom.
b. Electrcrnegativity is an Indicator of tire degree to whicla the nucleus of an atom attracts shared electrons.
c. TIe electronegativit-y of atonts decreases going from
left to right across a period.
d. tie electronegativity of atoms increases going dosvn
a. ‘tie electronegativit-y of a noble gas is greater than
the electronegativity of the halogen thor is in the
Answer the qnesrlosu below.
MHR . Unit t Matter, Chemical Trends, and Chewical llorrdinq
19. Nuclear reactors create highly unstable, or radioactive, Waste. Ths waste is formed when urat,iunr nuclei
in the fuel fission, or split, into smaller nuclei. Par
example, a uraniutn-235
U) nucleus might split
into a strontiunt-95
Sn) nucleus and a xenonl 37
( Xe) nucleus. Why are srrontiunr-95 and xenon-t37...