1.4. Ionisation energy
A subsection of Chemistry, 9701, through 1. Atomic structure
Listing 10 of 131 questions
The elements phosphorus, sulfur and chlorine are in Period 3 of the Periodic Table. Table 1.1 shows some properties of the elements P to Cl . The first ionisation energy of S is not shown. Table 1.1 property P S Cl number of electrons in 3p subshell total number of unpaired electrons first ionisation energy / kJ mol–1 formula of most common anion P3– S2– Cl – Complete Table 1.1 to show the number of electrons in the 3p subshell and the total number of unpaired electrons in an atom of P, S and Cl . Construct an equation to represent the first ionisation energy of P. Three possible values for the first ionisation energy of S are given. 1000 kJ mol–1 1160 kJ mol–1 1320 kJ mol–1 Circle the correct value. Explain your choice by comparing your chosen value to those of P and Cl . P3–, S2– and Cl – have the same number of electrons. Give the full electronic configuration of P3–. State the trend in ionic radius shown by P3–, S2– and Cl –. Explain your answer. A student does three tests on separate samples of NaCl . Complete Table 1.2 with the observations the student makes in each test. Table 1.2 test test observations addition of a few drops of Br22 addition of a few drops of concentrated H2SO4 addition of a few drops of dilute AgNO3 POCl3 shows similar chemical properties to PCl5. POCl3 has a melting point of 1°C and a boiling point of 106 °C. POCl3 reacts vigorously with water, forming misty fumes and an acidic solution. Explain how the information in suggests the structure and bonding of POCl3 is simple covalent. Construct an equation for the reaction of POCl3 with water. POCl3 + POCl3 contains a double covalent bond between P and O. Complete the dot-and-cross diagram, in , to show the bonding in POCl3. Show outer shell electrons only. O P Cl Cl Cl POCl3forms when PCl3reacts with O2. 2PCl3+ O22POCl3Table 1.3 gives some relevant data. Table 1.3 process value / kJ mol–1 enthalpy change of formation of PCl3–289 enthalpy change of formation of POCl3–592 O22O+496 Define enthalpy change of formation, ΔHf . Calculate the bond energy of P=O in POCl 3 using the data in Table 1.3. Show your working. bond energy of P=O = kJ mol–1
9701_w23_qp_21
THEORY
2023
Paper 2, Variant 1
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The elements silicon, phosphorus and sulfur are in Period 3 of the Periodic Table. Describe the variation in atomic radius from silicon to sulfur. The melting point of silicon is 1410 °C. The melting point of sulfur is 113 °C. Explain this difference. Table 1.1 shows some properties of the elements Si to S. The first ionisation energy of P is not shown. Table 1.1 property Si P S total number of electrons in s subshells total number of electrons in p subshells first ionisation energy / kJ mol–1 formula of most common chloride SiCl 4 PCl 5 SCl 2 Complete Table 1.1 to show the total number of s and p electrons in an atom of Si, P and S. Construct an equation to represent the first ionisation energy of Si. Three possible values for the first ionisation energy of P are given. 619 kJ mol–1 893 kJ mol–1 1060 kJ mol–1 Circle the correct value. Explain your choice, including a comparison of your chosen value to those of Si and S. SiCl 4 and PCl 5 each react with water, forming misty fumes. Identify the chemical responsible for the misty fumes. Predict the shape of the SCl 2 molecule.
9701_w23_qp_22
THEORY
2023
Paper 2, Variant 2
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The elements phosphorus, sulfur and chlorine are in Period 3 of the Periodic Table. Table 1.1 shows some properties of the elements P to Cl . The first ionisation energy of S is not shown. Table 1.1 property P S Cl number of electrons in 3p subshell total number of unpaired electrons first ionisation energy / kJ mol–1 formula of most common anion P3– S2– Cl – Complete Table 1.1 to show the number of electrons in the 3p subshell and the total number of unpaired electrons in an atom of P, S and Cl . Construct an equation to represent the first ionisation energy of P. Three possible values for the first ionisation energy of S are given. 1000 kJ mol–1 1160 kJ mol–1 1320 kJ mol–1 Circle the correct value. Explain your choice by comparing your chosen value to those of P and Cl . P3–, S2– and Cl – have the same number of electrons. Give the full electronic configuration of P3–. State the trend in ionic radius shown by P3–, S2– and Cl –. Explain your answer. A student does three tests on separate samples of NaCl . Complete Table 1.2 with the observations the student makes in each test. Table 1.2 test test observations addition of a few drops of Br22 addition of a few drops of concentrated H2SO4 addition of a few drops of dilute AgNO3 POCl3 shows similar chemical properties to PCl5. POCl3 has a melting point of 1°C and a boiling point of 106 °C. POCl3 reacts vigorously with water, forming misty fumes and an acidic solution. Explain how the information in suggests the structure and bonding of POCl3 is simple covalent. Construct an equation for the reaction of POCl3 with water. POCl3 + POCl3 contains a double covalent bond between P and O. Complete the dot-and-cross diagram, in , to show the bonding in POCl3. Show outer shell electrons only. O P Cl Cl Cl POCl3forms when PCl3reacts with O2. 2PCl3+ O22POCl3Table 1.3 gives some relevant data. Table 1.3 process value / kJ mol–1 enthalpy change of formation of PCl3–289 enthalpy change of formation of POCl3–592 O22O+496 Define enthalpy change of formation, ΔHf . Calculate the bond energy of P=O in POCl 3 using the data in Table 1.3. Show your working. bond energy of P=O = kJ mol–1
9701_w23_qp_23
THEORY
2023
Paper 2, Variant 3
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Questions Discovered
131