3.1 - Periodic Table

An outline of the periodic table is shown below:

Which of the following are the correct names for the groups labelled X, Y and Z?

Chromium appears to the right of vanadium in the periodic table, as shown below:

Which of the following statements is true?

• A.$\hspace{1em}$Cr atoms always have a higher atomic number and atomic mass than V atoms

• B.$\hspace{1em}$Cr atoms have a higher atomic mass than V atoms but the atomic number may be lower

• C.$\hspace{1em}$Cr atoms have a higher atomic number than V atoms but the atomic mass may be lower

• D.$\hspace{1em}$Cr atoms may have a lower atomic number or atomic mass than V atoms

Metalloid elements play important roles in electronic components, such as solar cells and computer chips. Which of the following is the correct definition of a metalloid?

• A.$\hspace{1em}$Elements with a mixture of metallic and non-metallic physical properties

• B.$\hspace{1em}$Elements that convert from metals to non-metals with changing temperature

• C.$\hspace{1em}$Metals found in the p block of the periodic table

• D.$\hspace{1em}$Metals with incomplete d subshells

For elements in the same row X or column Y of the periodic table, some features of the outer electron shell remain constant.

Which of the following is correct?

The atomic numbers in two periods of the d block of the periodic table are shown below:

Why does the atomic number increase by a larger amount across period 6 of the d block than across period 5?

• A.$\hspace{1em}$ In the period 6 lanthanoids, electrons are added to 7 f orbitals rather than the d subshell.

• B.$\hspace{1em}$ In the period 6 lanthanoids, electrons are added to 14 f orbitals rather than the d subshell.

• C.$\hspace{1em}$ In the period 6 actinoids, electrons are added to 7 f orbitals rather than the d subshell.

• D.$\hspace{1em}$ In the period 6 actinoids, electrons are added to 14 f orbitals rather than the d subshell.

Atom X is an isotope of an alkali metal. Which of the following is a possible symbol for atom X?

• A.$\hspace{1em}$

• B.$\hspace{1em}$

• C.$\hspace{1em}$

• D.$\hspace{1em}$

[Maximum mark: 8]

An atomic nucleus of element X is surrounded by electron shells, as shown below:

1. The diagram does not fully describe the electron configuration of the atom or ion or the identity of element X.

   1. State why it is not possible to determine the position of element X in the periodic table from the electron configuration alone. [1]
      

   2. An alternative method for describing the electron configuration of an atom or ion is to draw the orbitals as boxes and the electrons as arrows. The box-and-arrow diagram for a helium atom is shown below:

      Draw a similar diagram for the atom or ion of element X, including labels for the occupied subshells. [3]
      

   3. Suggest the block of the periodic table in which element X is likely to be found, giving a reason for your answer. [2]
      

2. Element X could be found in group 1 of the periodic table.

   1. State the name given to elements in group 1 of the periodic table. [1]
      
   2. State the most likely period number of element X, assuming that the electron configuration in the diagram is as close as possible to that of the neutral atom. [1]
      

The complete electron configuration of a neutral atom is shown below:

In which group and period of the periodic table would this element be found?

The condensed electron configuration of an element is$\ce{[Ar] {3d^{10}}{4s}^2{4p}^5}$.

Which statement is correct about this element?

• A. $\hspace{1em}$ It belongs to group 4

• B. $\hspace{1em}$ It belongs to group 15

• C. $\hspace{1em}$ It belongs to period 3

• D. $\hspace{1em}$ It belongs to period 4

How many fully occupied $p$ orbitals are there in selenium, Se, atom?

• A. $\hspace{1em}$ 2

• B. $\hspace{1em}$ 3

• C. $\hspace{1em}$ 7

• D. $\hspace{1em}$ 9

Which gives the correct observation when gaseous chlorine is bubbled through a sodium iodide solution?

• A. $\hspace{1em}$ Formation of a clear, colorless solution

• B. $\hspace{1em}$ Formation of a pale green solution

• C. $\hspace{1em}$ Deposits of a black solid

• D. $\hspace{1em}$ Formation of a dark red/brown solution

[Maximum mark: 8]

The period 3 elements magnesium, silicon and sulfur are found in the second, fourteenth and sixteenth columns of the periodic table.

1. State the name given to a column of elements in the periodic table. [1]
   

2. State how the numbers of electron shells and outer shell electrons vary across period 3. [2]
   

3. Selected physical properties of magnesium, silicon and sulfur are given in the table below:

Element	Appearance	Mechanical properties
Magnesium	Shiny, grey	Ductile
Silicon	Shiny, grey	Brittle
Sulfur	Dull, yellow	Brittle

Explain how the positions of the elements across period 3 help to explain their similarities and differences. [3]

4. Period 3 contains more elements than period 1 but is equal in size to period 2. Suggest why the number of elements increases between periods 1 and 2 but not between periods 2 and 3. [2]
   

[Maximum mark: 7]

Phosphorus is an element in group 15 of the periodic table.

1. State the total number of occupied p orbitals at all levels in an atom of phosphorus. [1]
   

2. Phosphorus, $\ce{P4}$, reacts with oxygen to form phosphorus oxide, $\ce{P4O10}$, by the following equation, $\ce{P4 + 5O2 → P4O10}$.

   1. Calculate the minimum volume of oxygen gas required to fully react with 16.7$g$ phosphorus at 273 $K$ and 100 $kPa$. [2]
      

   2. 20.4$g$ of phosphorus oxide was formed during this reaction. Calculate the percentage yield. [2]
      

3. Describe the acid-base nature of phosphorus oxide and use an equation to demonstrate this behaviour. [2]
   

[Maximum mark: 10]

Lithium metal is known to react vigorously with water.

1. Write a balanced equation for the reaction that occurs. [1]
   

2. State the block of the periodic table where lithium is found. [1]
   

3. If the resulting pH of the solution is 13.70, calculate the concentration of the lithium product formed in the reaction in (a). [2]
   

4. If the volume of the solution is equal to $1.5\ dm^{3}$, calculate the mass of solid Li required to reach a pH of 13.70. [2]
   

5. If an equivalent mass of lithium oxide was added to the same volume of water, calculate the new pH of the solution and whether this results in more or less $\ce{H+}$ concentration in solution compared to pH 13.70 for Li in water. [2]
   

6. Describe the bonding structure that exists in solid lithium. [1]
   

7. Describe the bonding structure that exists in solid lithium oxide. [1]
   

[Maximum mark: 10]

Iodine and astatine are both elements in group 17 of the periodic table.

1. State the name given to the elements in this group. [1]
   

2. Explain why the elements in group 17 are described as being in a different block of the periodic table than the elements in group 1, based on the electron configurations of their neutral atoms. [2]
   

3. The electron configuration of a neutral iodine atom is indicated by its location in the periodic table.

   1. The electron configuration of a neutral sodium atom can be written in condensed notation as [Ne] 3s$^1$. State the electron configuration, in condensed notation, of a neutral iodine atom. [3]
      
   2. Explain how the electron configuration of the neutral iodine atom is related to the period number and group number for this element. [2]
      

4. The following outline of the periodic table shows how elements in groups 13 to 18 can be placed in three categories, x, y and z, based on their physical properties.

$\hspace{1em}$ Suggest why the thermal conductivity of astatine is much greater than that of iodine, based on the locations of these elements in the periodic table. [2]

Which of the following is the electron configuration of a neutral atom in group 12 and period 6 of the periodic table?

• A.$\hspace{1em}$ [Xe] 4f$^{14}$ 6s$^2$

• B.$\hspace{1em}$ [Xe] 4f$^{14}$ 5d$^{10}$ 6s$^2$

• C.$\hspace{1em}$ [Rn] 5f$^{14}$ 7s$^2$

• D.$\hspace{1em}$ [Rn] 5f$^{14}$ 6d$^{10}$ 7s$^2$

[Maximum mark: 13]

Lithium metal is known to react vigorously with water.

1. Write a balanced equation for the reaction. [1]
   

2. State the block of the periodic table where lithium is found. [1]
   

3. If the resulting pH of the solution is $13.70$, calculate the concentration of the lithium product formed in reaction (a). [2]
   

4. If the volume of the solution is equal to $1.5\ dm^3$, calculate the mass of solid Li required to reach a pH of $13.70$. [2]
   

5. If an equivalent mass of lithium oxide was added to the same volume of water, calculate the new pH of the solution and whether this results in more or less $\ce{H+}$ concentration in solution compared to pH 13.70 for Li in water. [2]
   

6. Describe the bonding structure that exists in solid lithium. [1]
   

7. Describe the bonding structure that exists in solid lithium oxide. [1]
   

8. Lithium can also bond to acetate ions ($\ce{CH3COO-}$, a weak base).

   Calculate $\ce{K_b}$ for the acetate ion, $\ce{CH3COO-}$ if $\ce{pK_a}$ for $\ce{CH3COOH}$ is $4.76\ (K_w = 1.00 \times 10^{-14}\ mol^2\ dm^{-6}$ at $298K$). [1]
   

9. Calculate the initial concentration of the acetate ion, $\ce{CH3COO-}$, if $1.5\ g$ of lithium acetate is added to $1.0\ dm^3$ of water. [1]
   

10. Using the $\ce{K_b}$ calculated in (h) and the initial concentration of acetate ions in (i), calculate the concentration of hydroxide ions, $\ce{OH-}$ at equilibrium if $1.5\ g$ of lithium acetate is added to $1.0\ dm^3$ of water. [1]
    

[Maximum mark: 10]

The positions of selected elements in the s and d blocks are shown in the periodic table below:

1. State the electron configuration of a neutral atom of Fe, including orbitals in both the inner and outer shells. [3]
   

2. Atoms of Cu and K both contain one electron in the 4s subshell.

   Explain why copper is described as a d block element, whereas potassium is found in the s block. [2]
   

3. The elements Ac and Rf are separated by 14 elements in the f block of the periodic table.

   1. State the name given to the elements between Ac and Rf. [1]
      
   2. Explain why there are 14 elements between Ac and Rf. [2]
      

4. Fe and Cu both form atoms or ions with partially filled d subshells.

   1. State the name given to elements of this type. [1]
      
   2. Suggest why the name stated in (i) can also be applied to some of the 14 elements between Ac and Rf. [1]