CP CHEMISTRY
Periodic Table Review
1.
Answer Key
Development of the Periodic Table
Scientist
Contribution to Periodic Table
John Newland
Arranged elements by increasing atomic mass, found repeating
pattern every 8 elements, law of octaves
Dmitri
Mendeleev
Arranged elements by increasing atomic mass, made accurate
predictions about properties of missing elements, published work
first – so gets credit for developing the first periodic table
Henry Moseley
Arranged elements by increasing atomic number which corrected
problems with Mendeleev’s table (elements out of order based
on properties), his revisions lead to periodic law
2.
What is the periodic law?
A periodic repetition of chemical and physical properties of the elements
is observed when they are arranged by increasing atomic number.
3.
What are the columns in the periodic table called?
4.
What are the horizontal rows called? periods
5.
What are the representative elements? Groups 1A to 8A
6.
What are the transition elements? all Group B elements
7.
What are the properties of the metals?
shiny, good conductors, solid at room temperature, ductile and malleable
most elements are metals
8.
What are the metalloids?
found on stair step line (except Al), have chemical and physical properties
of both metals and nonmetals
groups/families
CP CHEMISTRY, Periodic Table Review, page 2
9.
What are the properties of the nonmetals?
generally gases or brittle, dull solids, poor conductors of heat and
electricity
10.
What are most elements classified as?
metals
11.
What are the differences between valence electrons and core electrons?
core electrons – found in the lower orbitals of an atom close to the
nucleus, are NOT involved in chemical reactions
valence electrons – found in highest principal energy level orbitals, are
the outer electrons of the atom, involved in chemical reactions and
contribute to the element’s chemical properties, electrons in s and p
orbitals
12.
Why do elements found in the same group have similar chemical properties?
they have the same number of valence electrons and similar end electron
configurations
13.
What does the period tell about an atom’s valence electrons?
period = energy level of the valence electrons
14.
What does the group number tell about an atom’s valence electrons?
group # = # of valence electrons
15.
Identify which elements are found in the following blocks on the table.
Block
s
p
Elements found in block
Group 1A (alkali metals) and Group 2A (alkaline earth metals), last
electrons go in s orbitals
Groups 3A – 8A, last electrons going into p orbitals
d
B Groups – Transition metals – last electrons going into d orbitals,
have valence electrons in s orbitals
f
Inner Transition metals at bottom of table – last electrons going into f
orbitals, have valence electrons in s orbitals
CP CHEMISTRY, Periodic Table Review, page 3
16.
What is the trend for atomic radii as you move across a period? Why?
Atomic Radius Decreases – each electron added going into same energy
level so added protons in nucleus pull them in more tightly
17.
What is the trend for atomic radii as you move down a group? Why?
Atomic Radius Increases – electrons going into higher energy levels so
size of atoms are increasing and core electrons shield the valence
electrons from the pull of the protons in the nucleus
18.
What happens to the size of the radius when an element’s atoms lose
electrons? Why?
when atom loses electrons – pulls remaining electrons in closer, so
positive ions are smaller than original atoms
19.
What happens to the size of the radius when an element’s atoms gain
electrons? Why?
when atom gains electrons – more negative charges repulse each other,
so negative ions are larger than original atoms
20.
What is the octet rule?
Atoms tend to gain, lose, or share electrons in order to acquire a full set of
8 valence electrons. (Fill s and p orbitals)
21.
What kind of ions do metals form? lose electrons, positive ions
22.
What kind of ions do nonmetals form? gain electrons, negative ions
23.
Give the charge on the ions formed by Groups 1A through 8A.
Group 1A – 1+, Group 2A – 2+, Group 3A – 3+, Group 4A – shares,
Group 5A – 3-, Group 6A – 2-, Group 7A – 1-, Group 8A - nothing
CP CHEMISTRY, Periodic Table Review, page 4
24.
What is ionization energy? What is first ionization energy?
Energy needed to remove an electron from a gaseous atom.
First ionization energy is the energy needed to remove the first electron
from an atom.
25.
What is the trend for first ionization energy as you move across a period?
Why?
Ionization Energy Increases – Atoms are smaller in size and hold onto
electrons more tightly as well as having fuller valences so harder to remove
valence electrons
26.
What is the trend for first ionization energy as you move down a group?
Why?
Ionization Energy Decreases – Atoms become larger as move down group
so valence electrons are in higher energy levels and with more core
electrons around nucleus are shielded from the pull of protons so it
becomes easier to pull off electrons
27.
What is electronegativity?
It indicates the relative ability of the atom to attract electrons in a chemical
bond. (Note – Noble gases do not react and do not form bonds, so they
are not considered to have electronegativities.)
28.
What is the trend for electronegativity as you move across a period? Why?
Electronegativity Increases – atoms have fuller and fuller valences as you
move across a period so they pull on electrons more tightly to achieve an
octet
29.
What is the trend for electronegativity as you move down a group? Why?
Electronegativity Decreases – atoms become much larger and have higher
energy level valences, so due to shielding they do not hold onto the
electrons in a bond as tightly as smaller atoms do