Exam Electrons and Periodic Table

Transcription

1 1-20 multiple choice. Answer on scantron short response. Answer on exam paper. All questions are 4 points each. 1. Which term is defined as the region in an atom where an electron is most likely to be located? A) nucleus B) orbital C) quanta D) spectra 2. Compared to the energy and charge of the electrons in the first shell of a Be atom, the electrons in the second shell of this atom have A) less energy and the same charge B) less energy and a different charge C) more energy and the same charge D) more energy and a different charge 3. Which element is paired with an excited- electron configuration for an atom of the element? A) Ca: B) Na: C) K: D) F: Rubidium and cesium have similar chemical properties because, in the ground, the atoms of both elements each have A) one electron in the outermost shell B) two electrons in the outermost shell C) one neutron in the nucleus D) two neutrons in the nucleus 5. What is the total number of valence electrons in an atom of germanium in the ground? A) 8 B) 2 C) 14 D) 4 6. Which ment describes the relative energy of the electrons in the shells of a calcium atom? A) An electron in the first shell has more energy than an electron in the second shell. B) An electron in the first shell has the same amount of energy as an electron in the second shell. C) An electron in the third shell has more energy than an electron in the second shell. D) An electron in the third shell has less energy than an electron in the second shell. 7. When an excited electron in an atom moves to the ground, the electron A) absorbs energy as it moves to a higher energy B) absorbs energy as it moves to a lower energy C) emits energy as it moves to a higher energy D) emits energy as it moves to a lower energy 8. The elements on the Periodic Table are arranged in order of increasing A) mass number B) atomic number C) number of isotopes D) number of valence electrons 9. Which list of elements contains a metal, a metalloid, a nonmetal, and a noble gas? A) Be, Si, Cl, Kr B) C, N, Ne, Ar C) K, Fe, B, F D) Na, Zn, As, Sb 10. Which two elements have the most similar chemical properties? A) Be and Mg B) Ca and Br C) Cl and Ar D) Na and P 11. An element that has a low first ionization energy and good conductivity of heat and electricity is classified as a A) metal B) metalloid C) nonmetal D) noble gas 12. Which two characteristics are associated with metals? A) low first ionization energy and low B) low first ionization energy and high C) high first ionization energy and low D) high first ionization energy and high

2 13. At STP, which element is solid, brittle, and a poor conductor of electricity? A) Al B) K C) Ne D) S 14. Which group on the Periodic Table has elements with atoms that tend not to bond with atoms of other elements? A) Group 1 B) Group 2 C) Group 17 D) Group Pure silicon is chemically classified as a metalloid because silicon A) is malleable and ductile B) is an excellent conductor of heat and electricity C) exhibits metallic and nonmetallic properties D) none of the above 16. What occurs when a magnesium atom becomes a magnesium ion? A) Electrons are gained and a positive ion is B) Electrons are gained and a negative ion is C) Electrons are lost and a positive ion is D) Electrons are lost and a negative ion is 17. Which atom has the largest atomic radius? A) potassium B) rubidium C) francium D) cesium 18. Which atom has the greatest attraction for the electrons in a chemical bond? A) hydrogen B) oxygen C) silicon D) sulfur 19. Which term represents the attraction one atom has for the electrons in a bond with another atom? A) B) electrical conductivity C) first ionization energy D) mechanical energy 20. Which element requires the least amount of energy to remove the most loosely held electron from a gaseous atom in the ground? A) bromine B) calcium C) sodium D) silver Exam Electrons and Periodic Table

3 Base your answers to questions 21 through 23 on the information below. The bright-line spectra for three elements and a mixture of elements are shown below. 21. State the total number of valence electrons in a cadmium atom in the ground. 22. Identify all the elements in the mixture. 23. Explain, in terms of both electrons and energy, how the bright-line spectrum of an element is produced.

4 Base your answers to questions 24 and 25 on the information below. The ionic radii of some Group 2 elements are given in the table below. 24. Explain, in terms of electrons, why the ionic radius of a Group 2 element is smaller than its atomic radius. 25. State the trend in ionic radius as the elements in Group 2 are considered in order of increasing atomic number.

5 Answer Key Electrons and Periodic Table Exam 1. B 2. C 3. C 4. A 5. D 6. C 7. D 8. B 9. A 10. A 11. A 12. A 13. D 14. D 15. C 16. C 17. C 18. B 19. A 20. C lithium and strontium 23. When electrons in an excited return to a lower energy, specific amounts of energy are emitted. These energies are associated with specific wavelengths of light that are characteristic of the bright-line spectrum of an element. Energy is emitted when excited electrons fall back to lower shells. 24. The valence electron shell of a Group 2 atom is lost when it becomes an ion. A Group 2 ion has two fewer electrons than the atom from which it was 25. As the atomic number of elements in Group 2 increases, the ionic radius increases. The ionic radius increases.