3.2 - Periodic Trends

Which chemical equation represents the definition of first ionization energy?

• A.$\hspace{1em}$X$_{(s)}$+ e$^-$ → X$^-_{(s)}$

• B.$\hspace{1em}$X$_{(s)}$→ X$^+_{(s)}$ + e$^-$

• C.$\hspace{1em}$X$_{(g)}$ → X$^+_{(g)}$ + e$^-$

• D.$\hspace{1em}$X$_{(g)}$+ e$^-$ → X$^-_{(g)}$

Which element would have the least attraction for a shared pair of electrons in a covalent bond?

• A.$\hspace{1em}$Carbon

• B.$\hspace{1em}$Nitrogen

• C.$\hspace{1em}$Oxygen

• D.$\hspace{1em}$Fluorine

A group 2 metal oxide dissolved in water would produce a solution that is:

• A.$\hspace{1em}$Acidic

• B.$\hspace{1em}$Basic

• C.$\hspace{1em}$Neutral

• D.$\hspace{1em}$Possibly either acidic or basic

The electron affinity of carbon is -122 $kJ\ mol^{-1}$, whereas the electron affinity of boron is -27 $kJ\ mol^{-1}$. Which statement below best explains this difference?

• A.$\hspace{1em}$Carbon has more protons resulting in an increased attraction for its valence electrons

• B.$\hspace{1em}$The electrons in boron are located in a lower energy level than carbon

• C.$\hspace{1em}$Boron has fewer electrons than carbon

• D.$\hspace{1em}$The trend decreases from left to right across the periodic table

[Maximum mark: 3]

The reaction shown below will not occur under standard conditions:

Br$_{2{(l)}}$ + 2 NaF$_{(aq)}$ → F$_{2{(g)}}$ + 2 NaBr$_{(aq)}$

1. State a balanced chemical equation for a reaction that will occur, producing sodium bromide. [2]
   

2. Describe an observation that allows the progress of the monitoring of the reaction written in part (a). [1]
   

Which of the following statements regarding the periodic table are correct?

• I. Anions have larger ionic radii than the atomic radius of their parent atom
  II. Elements in the periodic table are arranged according to their number of protons
  III. Elements within the same period will have similar physical properties

• A.$\hspace{1em}$I, II, and III

• B.$\hspace{1em}$I and II only

• C.$\hspace{1em}$I and III only

• D.$\hspace{1em}$II and III only

[Maxium mark: 9]

The table below contains data for the elements nitrogen, fluorine, sulfur and chlorine in no particular order:

Element	Atomic Radius (10$^{-12}$ $m$)	First Ionization Energy ($kJ\ mol^{-1}$)
1	71	1402
2	104	1000
3	100	1251
4	60	1681

1. Identify element 2 and justify your answer using the atomic radius and the first ionization energy data shown. [3]
   

2. 1. Identify the number of valence electrons for element 1 and justify your answer using
      the atomic radius and first ionization energy data shown. [2]
      

   2. State the electron configuration for the common ion formed from element 1. [1]
      

   3. Using section 9 (Section 10- 2025 Syllabus) in the data booklet, compare the size of the ionic radius of the common ion formed from element 1 to its atomic radius. Explain this change in size.[2]
      

3. An electron affinity for element 1 is not published and the electron affinity for element 4 is -328$kJ\ mol^{-1}$. In terms of atomic structure, explain why element 1 does not have a value for electron affinity. [1]
   

Which of the following does NOT have two valence electrons?

• A.$\hspace{1em}$Al$^+$

• B.$\hspace{1em}$Zn

• C.$\hspace{1em}$Ca

• D.$\hspace{1em}$Sc$^{3+}$

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

Which of the following statements regarding the melting points of elements are correct?

• I.$\hspace{1em}$ Group 17 melting points increase down the group due to increased covalent bond strength
  II.$\hspace{0.9em}$ Lithium has a higher melting point than potassium
  III.$\hspace{0.8em}$ Bromine has a higher melting point than chlorine

• A.$\hspace{1em}$I, II, and III

• B.$\hspace{1em}$I and II only

• C.$\hspace{1em}$II and III only

• D.$\hspace{1em}$II only

[Maximum mark: 8]

1. Bromine has a relative atomic mass of 79.90 and two common isotopes $^{79}$Br and $^{81}$Br. Calculate the percentage abundance of the $^{81}$Br isotope. [2]
   

2. State the equation for the first electron affinity of iodine. [1]
   

3. Describe and explain the trend in the magnitude of electron affinity from fluorine to iodine. [3]
   

4. Fluorine reacts with sodium iodide. State the net ionic equation for this reaction and name the type of reaction. [2]
   

[Maximum marks: 10]

Magnesium is an element in group 2 of the periodic table.

1. State the full electron configuration for magnesium and the block it can be found in the periodic table. [2]
   

2. Explain how successive ionization energies can prove that magnesium is in group 2 and period 3 of the periodic table. [3]
   

3. State the equation for the second ionization energy of magnesium. [1]
   

4. State an equation for the reaction between magnesium oxide and water, and comment on the pH of the resultant solution. [2]
   

5. By referring to their relative ionization energies, compare the metallic behavior of magnesium to calcium and beryllium (values from the data booklet are not required). [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]
   

Which of the following single replacement reactions will NOT occur?

• A.$\hspace{1em}$F$_2{_{(g)}}$+ 2NaBr${_{(aq)}}$ → Br$_2{_{(l)}}$+ 2NaF${_{(aq)}}$

• B.$\hspace{1em}$K${_{(s)}}$+ NaI${_{(aq)}}$ → Na${_{(s)}}$+ KI${_{(aq)}}$

• C.$\hspace{1em}$Rb${_{(s)}}$+ LiCl${_{(aq)}}$ → Li${_{(s)}}$+ RbCl${_{(aq)}}$

• D.$\hspace{1em}$I$_2{_{(s)}}$+ CaBr$_2{_{(aq)}}$ → Br$_2{_{(l)}}$+ CaI$_2{_{(aq)}}$

Which statement regarding the periodic table is true?

• A.$\hspace{1em}$Atomic radius increases across a period

• B.$\hspace{1em}$Selenium (Se) has a higher ionization energy than sulfur (S)

• C.$\hspace{1em}$Nonmetal oxides produce acidic solutions when dissolved in water

• D.$\hspace{1em}$Copper (Cu) is considered to be more metallic than cesium (Cs)

Which is in the correct order from smallest to largest radius?

• A.$\hspace{1em}$Ca$^{2+}$, Na$^+$, Ne, O$^{2-}$

• B.$\hspace{1em}$O$^{2-}$, Ne, Ca$^{2+}$, Na$^+$

• C.$\hspace{1em}$Ne, Na$^+$, O$^{2-}$, Ca$^{2+}$

• D.$\hspace{1em}$Na$^+$, Ne, O$^{2-}$, Ca$^{2+}$

[Maximum mark:6]

The oxides of two period 3 elements, X and Y, react in water according to the equations below.

• I.$\hspace{1em}$ XO$_2{_{(s)}}$ + H$_2$O${_{(l)}}$ → H$_2$XO$_{3{(aq)}}$
• II.$\hspace{1em}$ YO$_{(s)}$ + H$_2$O${_{(l)}}$ → Y(OH)$_{2{(aq)}}$

1. Identify elements X and Y. Justify your response. [4]
   

2. Predict whether element X or Y would have a higher melting point. Justify your prediction. [2]
   

[Maximum mark: 5]

The successive ionization energies for element X is shown in the table below:

Successive Ionization Energies ($kJ\ mol^{-1}$):

1st IE	2nd IE	3rd IE	4th IE	5th IE	6th IE	7th IE	8th IE
1000	2252	3363	4556	7004	8496	27108	31724

1. Write the equation that represents the 2nd ionization energy of element X. [1]
   

2. Predict the number of valence electrons for element X and justify your response. [2]
   

3. Another element, Y, is found below and in the same group as element X in the periodic table. The electronegativity value of element Y is 2.6. Predict a reasonable value for the electronegativity value of element X. Explain your reasoning.[2]
   

Which statement(s) about the reaction of $\ce{P4O10}$ with water is(are) correct?

• I. $\hspace{1em}$ The pH of the resulting solution is below 7.00 at $25\degree$ C
• II. $\hspace{.7em}$ The product formed is $\ce{H3PO4}$
• III. $\hspace{.4em}$ $\ce{P4O10}$ is classified as an amphoteric oxide

• A. $\hspace{1em}$ I only

• B. $\hspace{1em}$ II only

• C. $\hspace{1em}$ III only

• D. $\hspace{1em}$ I and II only