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Name: ______________________________ Pd: _____ Ast: _____
Physical Science Honors: Periodic Table Study Guide
How did Mendeleev originally organize his periodic table?
He arranged elements in order by increasing atomic mass, then grouped them by similar characteristics
What made Mendeleev’s periodic table better than prior attempts to organize the elements?
Mendeleev’s periodic table made it possible to predict the properties of elements based on their position within
the table. He even predicted the existence and properties of undiscovered elements using his table.
What is the main difference between the modern periodic table and the one Mendeleev came up with?
Elements are ordered by increasing atomic number instead of atomic mass. This is important because it is the
number of protons (atomic number) that differentiates elements from one another.
Why do we call it the “periodic” table?
The word, “periodic”, means a regular repeating pattern. The characteristics of elements in each period exhibit a
regular repeating pattern.
Identify the information included in the boxes on the periodic table:
26
Atomic Number
Fe
Element Symbol
Iron
Element Name
55.847
Atomic Mass
6) Why do some of the element symbols not seem to make sense based on the name of the element?
Some element symbols reflect the Latin name for the element (ex: Lead (Pb), Iron (Fe), Silver (Ag))
7) What determines the atomic number? Why is this important?
The atomic number reflects the number of protons in the nucleus. This is what makes each element unique.
8) What determines the atomic mass? Why is this not often a whole number?
The atomic mass is determined by the number of protons and neutrons in the nucleus. It is an AVERAGE of all the
different versions (isotopes) of that element (they can have different numbers of neutrons).
9) What are the vertical columns on the periodic table called? (give both names)
The vertical columns are called “groups” or “families”.
10) What is special about elements in the same group?
Elements within the same group share similar characteristics.
11) What are the horizontal rows called?
The horizontal rows are called periods. This is what gives the periodic table its name.
12) What is the pattern of protons in the periodic table?
The number of protons increases by one left to right.
13) What is the pattern of atomic mass in the periodic table?
The atomic mass generally increases left to right, with a few exceptions.
14) What is the pattern of characteristics in the periodic table?
Elements in the same group share similar characteristics.
15) What are valence electrons?
Valence electrons are the electrons located on the outer shell, farthest from the nucleus. They are important in
chemical bonding.
16) What is the pattern of density in the periodic table?
The density of elements tends to increase going down each group, with the least dense at the top and the most
dense at the bottom of the group.
17) What are valence electrons?
Valence electrons are the electrons located on the outer shell, farthest from the nucleus. They are important in
chemical bonding.
18) What is the pattern of valence electrons in the periodic table?
Elements in the same group have the same number of valence electrons.
19) What are the implications on the number of sub-atomic particles if we assume we are dealing with “neutral atoms”?
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A neutral atom must have an equal number of protons and electrons for the charges to balance. This means that
the atomic number tells us both the number of protons AND the number of electrons in a neutral atom.
How many total electrons can fit on each orbital?
s = 2, p = 6, d = 10, f = 14
Why do the orbitals fill up in a strange order (ex: “4s” comes before “3d”)?
In some places, the energy levels overlap each other, causing orbitals in a higher layer to fill up before orbitals in a
lower layer. The orbitals fill up in order from lower to higher energy, so where they overlap, the lower energy
orbital (4s) will fill up before the higher energy orbital (3d). The order that the orbitals fill up is reflected in the
electron configuration chart.
Why is the periodic table organized into blocks?
The blocks in the periodic table represent the electron configuration. Each section belongs to a certain orbital (ie:
the “s” block, the “p” block, the “d” block, or the “f” block).
The electron configuration for manganese is 1s22s22p63s23p64s23d5. Explain what this means in terms of the location
of electrons in the atom.
This means that a neutral atom of manganese has 2 electrons on the first energy level, 8 electrons on the second
energy level (2 on the s and 6 on the p orbitals), 13 electrons on the third energy level (2 on the s, 6 on the p, and 5
on the d orbital), and two electrons on the fourth energy level (both on the s orbital).
Write the electron configuration for gallium.
Ga31: 1s22s22p63s23p64s23d104p1 or [Ar]4s23d104p1
Write the electron configuration for einsteinium.
Es99: 1s22s22p63s23p64s23d104p65s24d105p66s24f145d106p67s25f11 or [Rn]7s25f11
What is the purpose of a Bohr diagram?
A Bohr diagram shows how many electrons are on each shell, or energy level of the atom.
Draw a Bohr diagram for sodium.
28) Draw a Bohr diagram for krypton.
29) Explain the trick to determining the number of valence electrons an element has.
The one’s digit of the group number for groups 1-2 and 13-18 will tell you how many valence electrons the
element has.
30) Describe the octet rule.
The octet rule states that the outer shell is full when it has 8 valence electrons. Atoms become more stable when
their outer shell is “full”.
31) How many valence electrons will a neutral atom of aluminum have? How do you know?
A neutral atom of aluminum will have 3 valence electrons because it is in group 13.
32) Draw an electron dot diagram for oxygen.
33) Draw an electron dot diagram for lithium.
34) What does the location of the dots in an electron dot diagram represent (Why do the first two go on the right and
the others on the remaining three sides)?
The first two dots on the right represent the s orbital, while the other six represent the p orbital.
35) Why is helium located in group 18 even though it only has 2 valence electrons instead of 8 like the rest of group 18?
Helium is a noble gas even though it only has 2 valence electrons because the 1st energy level only has an s orbital.