UNIT 3: Electrons Lesson 5: Atomic Radius and Ionic Radius Do Now: By the end of today, you will have an answer to: How the does the radius change when an atom becomes an ion? 1. How many protons, neutrons, and electrons does Mg 2+ have? Protons: Neutrons: Electrons: 2. How is Mg 2+ different from an Mg atom? 3. Explain, in terms of subatomic particles and energy states, how a bright-line spectrum of an element is produced. CATALYST ACTIVITY 1. How many electron shells does lithium have? 2. How many electron shells does rubidium have? 3. If atomic radius refers to the size of an atom, how do you think the atomic radius of lithium will compare to the atomic radius of rubidium? Defend your answer. 4. How many electron shells does a magnesium atom have? 5. What is the electron configuration for a magnesium ion? 6. How many electron shells does a magnesium ion have? 7. If ionic radius refers to the size of an ion, how does the ionic radius of magnesium compare to the atomic radius of magnesium. In other words, which one would be greater: the ionic radius or the atomic radius? Explain your answer in terms of electron configuration.
ATOMIC RADIUS: QUESTIONS What is it? NOTES What does atomic radius depend on? WHY? EXAMPLE: IONIC RADIUS: QUESTIONS What is it? NOTES How does the ionic radius compare to the atomic radius of the same element? WHY? EXAMPLE:
CW 3.5- Atomic Radius and Ionization Energy 10 points Directions: Answer all questions based on your knowledge of chemistry. 1. An atom of which element has the largest atomic radius? (1) Fe (3) Mg (2) Si (4) Zn 2. What occurs when an atom loses an electron? (1) The atom s radius decreases and the atom becomes a negative ion. (2) The atom s radius decreases and the atom becomes a positive ion. (3) The atom s radius increases and the atom becomes a negative ion. (4) The atom s radius increases and the atom becomes a positive ion. 3. What changes occur as a cadmium atom, Cd, becomes a cadmium ion, Cd 2+? (1) The Cd atom gains two electrons and its radius decreases. (2) The Cd atom gains two electrons and its radius increases. (3) The Cd atom loses two electrons and its radius decreases. (4) The Cd atom loses two electrons and is radius increases. 4. As the atomic number increases with Group 15 on the Periodic Table, atomic radius (1) Decreases, only (2) Increases, only (3) Decreases, then increases (4) Increases, then decreases 5. What occurs when an atom of chlorine forms a chloride ion? (1) The chlorine atom gains an electron, and its radius becomes smaller. (2) The chlorine atom gains an electron, and its radius becomes larger (3) The chlorine atom loses an electron, and its radius becomes smaller. (4) The chlorine atom loses an electron, and its radius becomes larger. 6. Explain, in terms of atomic structure, why the atomic radius of iodine is greater than the atomic radius of fluorine. 7. State, in terms of number of electron shells, why the radius of a strontium atom in the ground state is larger than the radius of a magnesium atom in the ground state. [1] 8. Explain, in terms of subatomic particles, why the radius of a chloride ion is larger than the radius of a chlorine atom. [1] 9. Explain, in terms of atomic structure, why the radius of an Na atom is larger than the radius of an Na + ion. [1] Base your answers to questions 9 and 10 on the information below. The atomic and ionic radii for sodium and chlorine are shown in the table below.
10. Write the ground state electron configuration for the ion that has a radius of 181 picometers. [1] The ionic radii of some Group 2 elements are given in the table below. 11. On the grid below, mark an appropriate scale on the axis labeled Ionic Radius (pm). 12. On the same grid, plot the data from the data table. Circle and connect the points. 13. Estimate the ionic radius of strontium. 14. State the trend in ionic radius as the elements in Group 2 are considered in order of increasing atomic number. 15. Explain, in terms of ionic structure, why Be has a smaller atomic radius than Mg. 16. Explain, in terms of electrons, why the ionic radius of a Group 2 element is smaller than its atomic radius.
Exit Ticket Quiz 3.5- Atomic Radius and Ionic Radius 3 points 1. A metal, M, was obtained from a compound in a rock sample. Experiments have determine that this element is a member of Group 2 on the Periodic Table of Elements. Explain why the radius of a positive ion of element M is smaller than the radius of an atom of element M. 2. Which list of elements from Group 2 on the Periodic Table is arranged in order of increasing atomic radius? (1) Be, Mg, Ca (2) Ca, Mg, Be (3) Ba, Ra, Sr (4) Sr, Ra, Ba 3. An ion of which element has a larger radius than an atom of the same element? (1) Aluminum (2) Chlorine (3) Magnesium (4) Sodium Exit Ticket Quiz 3.5- Atomic Radius and Ionic Radius 3 points 1. A metal, M, was obtained from a compound in a rock sample. Experiments have determine that this element is a member of Group 2 on the Periodic Table of Elements. Explain why the radius of a positive ion of element M is smaller than the radius of an atom of element M. 2. Which list of elements from Group 2 on the Periodic Table is arranged in order of increasing atomic radius? (1) Be, Mg, Ca (2) Ca, Mg, Be (3) Ba, Ra, Sr (4) Sr, Ra, Ba 3. An ion of which element has a larger radius than an atom of the same element? (1) Aluminum (2) Chlorine (3) Magnesium (4) Sodium
HW 3.5- Atomic Radius and Ionization Energy 20 points Directions: Answer all questions based the information below. The ionic radii of some Group 2 elements are given in the table below. 17. On the grid below, mark an appropriate scale on the axis labeled Ionic Radius (pm). 18. On the same grid, plot the data from the data table. Circle and connect the points. 19. Estimate the ionic radius of strontium. 20. State the trend in ionic radius as the elements in Group 2 are considered in order of increasing atomic number. 21. Explain, in terms of ionic structure, why Be has a smaller atomic radius than Mg. 22. Explain, in terms of electrons, why the ionic radius of a Group 2 element is smaller than its atomic radius.