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This is placeholder text. To change this content, double-click on the element and click Change Content. < Back This is a Title 02 This is placeholder text. To change this content, double-click on the element and click Change Content. This is placeholder text. To change this content, double-click on the element and click Change Content. Want to view and manage all your collections? Click on the Content Manager button in the Add panel on the left. Here, you can make changes to your content, add new fields, create dynamic pages and more. You can create as many collections as you need. Your collection is already set up for you with fields and content. Add your own, or import content from a CSV file. Add fields for any type of content you want to display, such as rich text, images, videos and more. You can also collect and store information from your site visitors using input elements like custom forms and fields. Be sure to click Sync after making changes in a collection, so visitors can see your newest content on your live site. Preview your site to check that all your elements are displaying content from the right collection fields. Previous Next

Chromatograms,criteria of purity,chromatogram,melting point and boiling point and purity,Rf Values,Foodstuff and drugs purity, IGCSE CHEMISTRY CAMBRIDGE 2.Experimental Techniques 2.2 Criteria of Purity Back to Chapter 2 Menu Demonstrate knowledge and understanding of paper chromatography Interpret simple chromatograms Baseline should be drawn in pencil so it does not dissolve in the solvent Download as PDF file

0336cea9-9039-47a1-8331-57402cb43a0d Reaction of Alkali metals with water. Summary Generally: 2M(s) + 2H2O(l) → 2M+ (aq) + 2OH- (aq) + H2(g) alkali metal + water → alkali metal hydroxide + hydrogen Observations for the reaction of alkali metal with water:  Piece of metal floats (alkali metals have low density).  Piece of metal darts around.  A hissing sound is heard due to the evolution of a gas.  If red litmus paper is dipped in the solution, the paper turns blue due to the formation of the alkali metal hydroxide.  If few drops of phenolphthalein indicator are added to the water solution turns pink due to the formation of alkali metal hydroxide.  If the gas produced is tested with a lit splint, it burns with a squeaky pop sound.

fa3131e0-e5c5-48a1-8d12-f206f9b4c6d2 Activation energy: definition in SABIS Summary as activated complex (AC). The AC i activated complex s found at the highest point of the potential energy curve. It is an unstable structure with energy higher than both reactants and products.

6de5efa8-0086-4f23-9235-a10af8abad04 Melting/Fusion Summary The change of a substance from a solid to a liquid state at a specific temperature.

101f067d-e23b-4529-a0de-2daaf0a3acf4 < Back Previous Next Organic Chemistry Next Topic

6b4d40ef-0011-442b-b2d6-ae15b26f0831 Sublimation Summary The process of a substance changing directly from a solid to a gaseous state at a specific temperature.

⚛️ Lesson 7 ⚛️ < Back Atomic Structure Lesson 7 ⚛️ Lesson 7 ⚛️ Section Test 1 , Test 2 Previous Next Quiz 1 : Atomic Structure, Isotopes, and Subatomic Particles 1️⃣ Boron is an element in Group 13 of the Periodic Table. a) Define the term "isotope." 🌟 b) Provide the number of i) protons, ii) neutrons, and iii) electrons in one neutral atom of the isotope 11B. 🧪 c) State the relative masses and charges of: i) an electron 🌌 ii) a neutron 🌌 iii) a proton 🌌 2️⃣ Zirconium (Zr) and hafnium (Hf) are metals. a) i) Write the isotopic symbol for the isotope of zirconium with 40 protons and 91 nucleons. 🌟 ii) How many neutrons are present in one atom of this isotope? 🌟 b) Hafnium ions, 18072Hf2+, are produced in a mass spectrometer. How many electrons are present in one of these hafnium ions? 🌟 c) Describe the behavior of a beam of protons passing through the gap between charged plates and explain what happens when a beam of neutrons passes through the same gap. 🌌 3️⃣ a) Describe the structure of an atom, including details of the subatomic particles present. 🌟 b) Explain the terms atomic number and nucleon number. 🌌 c) Copy and complete the table: Neutral atom | Atomic number | Nucleon number | Numbers of each subatomic particle present Mg | 12 | 24 | Al | 13 | 27 | d) Explain why atoms are neutral. 🌌 e) Explain why an oxygen atom cannot have 9 protons. 🌌 f) Explain why electrons are not used when calculating the relative mass of an atom. 🌌 4️⃣ The symbols below describe two isotopes of the element uranium. 235 92U 238 92U a) Define the term "isotope." 🌟 b) i) In what ways are these two isotopes of uranium identical? 🌟 ii) In what ways do they differ? 🌟 c) State the number of electrons present in one U2+ ion. 🌌 5️⃣ The table below shows the two naturally occurring isotopes of chlorine. a) Copy and complete the table: 35 17Cl 37 17Cl number of protons | number of electrons | number of neutrons | b) Based on the relative atomic mass of chlorine (35.5), what can you infer about the relative abundance of the two naturally occurring isotopes of chlorine? 🌟 c) i) Explain why a magnesium ion is positively charged. 🌌 ii) Explain why a chloride ion has a single negative charge. 🌌 Note: 🌟 indicates questions with fill-in-the-blank format, and 🌌 indicates multiple-choice questions. Good luck! 🧪🔬 Answers 1️⃣ Boron is an element in Group 13 of the Periodic Table. a) The term "isotope" refers to different forms of an element that have the same number of protons but different numbers of neutrons. b) i) Protons: 5, ii) Neutrons: 6, iii) Electrons: 5. 2️⃣ Zirconium (Zr) and hafnium (Hf) are metals. a) i) The isotopic symbol for the isotope of zirconium with 40 protons and 91 nucleons is 9123Zr. ii) The number of neutrons in one atom of this isotope is 51. b) The hafnium ion (18072Hf2+) contains 68 electrons. c) - i) The beam of protons passing through the gap between the charged plates is deflected towards the negative plate due to the electric field. ii) When a beam of neutrons passes through the gap between the charged plates, it remains unaffected as neutrons are neutral particles. 3️⃣ a) The structure of an atom consists of subatomic particles: protons and neutrons located in the nucleus, and electrons orbiting the nucleus. b) - Atomic number represents the number of protons in an atom's nucleus. Nucleon number (mass number) represents the total number of protons and neutrons in an atom's nucleus. c) Neutral atom | Atomic number | Nucleon number | Numbers of each subatomic particle present Mg | 12 | 24 | 12 protons, 12 neutrons, 12 electrons Al | 13 | 27 | 13 protons, 14 neutrons, 13 electrons d) Atoms are neutral because they have an equal number of protons and electrons, resulting in a net charge of zero. e) An oxygen atom cannot have 9 protons because the number of protons determines the element's identity, and oxygen is defined by having 8 protons. f) Electrons are not used when calculating the relative mass of an atom because their mass is significantly smaller compared to protons and neutrons. Their contribution to the total mass is negligible. 4️⃣ The symbols below describe two isotopes of the element uranium. 235 92U 238 92U a) The term "isotope" refers to different forms of an element that have the same number of protons but different numbers of neutrons. b) - i) These two isotopes of uranium are identical in terms of the number of protons (92) and the chemical properties. ii) They differ in terms of their mass number (235 and 238) and the number of neutrons. c) One U2+ ion has 90 electrons. 5️⃣ The table below shows the two naturally occurring isotopes of chlorine. a) 35 17Cl 37 17Cl number of protons | 17 | 17 number of electrons | 17 | 17 number of neutrons | 18 | 20 b) The relative atomic mass of 35.5 suggests that the two isotopes of chlorine have approximately equal abundance. c) - i) A magnesium ion is positively charged because it has lost two electrons, resulting in more protons than electrons. ii) A chloride ion has a single negative charge because it has gained one electron, resulting in more electrons than protons. Well done on completing the quiz! Keep up the great work! 🔬🎉 Quiz 2 : Atomic Structure, Isotopes, and Subatomic Particles 1️⃣ Boron is an element in Group 13 of the Periodic Table. a) Boron has two isotopes. 🔄❓ What do you understand by the term isotope ? [1] b) State the number of: i) protons, ii) neutrons, and iii) electrons in one neutral atom of the isotope 11 5B. [3] c) State the relative masses and charges of: i) an electron, ii) a neutron, and iii) a proton. [2] 2️⃣ Zirconium, Zr, and hafnium, Hf, are metals. An isotope of zirconium has 40 protons and 91 nucleons. ⚛️❓ a) i) Write the isotopic symbol for this isotope of zirconium. [1] ii) How many neutrons are present in one atom of this isotope? [1] b) Hafnium ions, 18072Hf2+ , are produced in a mass spectrometer. How many electrons are present in one of these hafnium ions? [1] c) The subatomic particles present in zirconium and hafnium are electrons, neutrons, and protons. A beam of protons is fired into an electric field produced by two charged plates, as shown in the diagram below: ) Describe how the beam of protons behaves when it passes through the gap between the charged plates. Explain your answer. [2] ii) Describe and explain what happens when a beam of neutrons passes through the gap between the charged plates. [2] 3️⃣ a) Describe the structure of an atom, giving details of the subatomic particles present. 🏢🔬 [6] b) Explain the terms: Atomic number, and Nucleon number. [2] c) Copy and complete the table: d) Explain why atoms are neutral. [1] e) An oxygen atom has 8 protons in its nucleus. Explain why it cannot have 9 protons. [1] f) When calculating the relative mass of an atom, the electrons are not used in the calculation. Explain why not. [1] 4️⃣ The symbols below describe two isotopes of the element uranium. 235 92U 238 92 U a) State the meaning of the term isotope . [1] b) i) In what ways are these two isotopes of uranium identical? [2] ii) In what ways do they differ? [2] c) In a mass spectrometer, uranium atoms can be converted to uranium ions, U2+ . State the number of electrons present in one U2+ ion. [1] 5️⃣ The table below shows the two naturally occurring isotopes of chlorine. a) Copy and complete the table: b) The relative atomic mass of chlorine is 35.5. What does this tell you about the relative abundance of the two naturally occurring isotopes of chlorine? [2] c) Magnesium chloride contains magnesium ions, Mg2+ , and chloride ions, Cl– . i) Explain why a magnesium ion is positively charged. [1] ii) Explain why a chloride ion has a single negative charge. [2] Total = 50 🌟 ✨ Quiz Answers: ✨ 1a) Isotope refers to different forms of an element with the same number of protons but different numbers of neutrons. 1b) i) Protons: 5, ii) Neutrons: 6, iii) Electrons: 5 1c) i) Electron: Relative mass = 1/1837 amu, Charge = -1 e ii) Neutron: Relative mass = 1 amu, Charge = 0 iii) Proton: Relative mass = 1 amu, Charge = +1 e 2a) i) 91Zr ii) Neutrons: 51 2b) Electrons: 72 2c) i) The beam of protons is deflected towards the negatively charged plate due to their positive charge. ii) Neutrons are electrically neutral, so they are not affected by the electric field and continue on a straight path. 3a) An atom consists of a nucleus (containing protons and neutrons) surrounded by electrons in energy levels or shells. 3b) - Atomic number: Number of protons in an atom's nucleus. - Nucleon number: Total number of protons and neutrons in an atom's nucleus. 3c) e) The number of protons determines the identity of an element. Changing the number of protons would result in a different element. f) Relative mass calculations focus on the mass of the nucleus, which is primarily determined by protons and neutrons. Electrons contribute negligible mass. 4a) Isotope refers to different forms of an element with the same number of protons but different numbers of neutrons. 4b) i) Both isotopes have the same number of protons (92) and belong to the element uranium. ii) They differ in the number of neutrons: Uranium-235 has 143 neutrons, while uranium-238 has 146 neutrons. 4c) U2+ ion has 90 electrons. 5a) | | 35 | 17 Cl | 37 | 17 b) The relative atomic mass of 35.5 indicates that there is a mixture of the two isotopes of chlorine, with a higher abundance of the isotope with a mass number of 35.c) i) A magnesium ion is positively charged because it has lost two electrons, resulting in a net positive charge. ii) A chloride ion has a single negative charge because it has gained one electron, resulting in a net negative charge.I hope you enjoyed the quiz! 🎉

SABIS Grade 10 Diagnostics T1