Page 133 - Canadian BC Science 9

Developing Skills
42. Draw a diagram of an atom containing seven protons, eight neutrons, and as many electrons as are needed to make the atom neutral. Show the correct number of electrons in each energy level.
43. Explain why sodium and chlorine atoms are extremely reactive but sodium ions and chloride ions are not. (Hint: Refer to the number of valence electrons in your explanation.)
44. Use a periodic table to find the atomic number, atomic mass, and most common ion charge for these elements.
(a) iron
(b) gold (c) Cu (d) U
45. Use a periodic table to identify these elements:
(a) the metal in period 4, group 2
(b) the non-metal in period 3, group 17
(c) the element that has an atomic number
of 13
(d) the element that has an atomic mass of
Pause and Reflect
Even though it is difficult to observe atoms without special equipment, the atomic theory describes our current understanding of atoms. How has the use of models helped explain the structure of atoms?
46. (a)
19.0 amu
Draw a Bohr model diagram of each of the following atoms: (a) O (b) F (c) Ne (d) K (e) Mg
(b) Draw a Bohr model diagram of each of the following ions: (a) O2􏰁 (b) F􏰁
(c) Na􏰀 (d) Mg2􏰀
(c) Compare the pattern of electrons in atoms to the pattern of electrons in ions.
Unit 1 Review • MHR 115