Biology Case Study
Case Study 1 1. Johnny has seen the words Sodium Chloride before in his science class with the periodic table. 2. Johnny couldn’t find Sodium Chloride on the periodic table because Sodium Chloride is a molecule made up of two atoms: Sodium and Chloride. 3. Sodium Chloride represents two atoms that together form a molecule: NaCl.
Na: Sodium and Cl: Chloride 4. An ionic bond occurs when two or more ions (an atom whose number of elections differs from its number of protons) bond together because of their opposite charge. They are drawn to each other like magnets because of their opposite charge. 5. Sodium Chloride came about because Sodium, a positively charged ion, has one electron in its outermost shell and Chlorine, a negatively charged ion, has seven electrons in its outmost shell. Sodium transfers the one electron to the Chlorine because in order for Sodium to have a full shell it would have needed seven more electrons to complete its shell. So instead in bonding with the Chlorine, its shell was completed and the ions were “happy”. 6. Johnny can’t find water on the periodic table because water is a molecule made up of two different atoms: hydrogen and oxygen. 7. The chemical formula for one water molecule is: H2O. H2O means that it took two hydrogen atoms to bond with one oxygen atom to create the water molecule. 8. The bond that is represented by the water molecule is a covalent bond. A covalent bond occurs when two atoms link together through sharing electrons. This occurs because atoms always want to have a full outer shell and the oxygen atom has only six electrons in its outer shell. In order to get a full shell, the oxygen atom links together with the two hydrogen atoms who have one electron a piece in the their outer shells and when bonded together all of the atoms have full outer shells. 9. a. Atomic Mass: H: 2 O: 16
b. Atomic Number: H:1 O:8
c. Number of Protons: H: 1 O:8
d. Number of Neutrons:H:0 O:8
e.
Na: Sodium and Cl: Chloride 4. An ionic bond occurs when two or more ions (an atom whose number of elections differs from its number of protons) bond together because of their opposite charge. They are drawn to each other like magnets because of their opposite charge. 5. Sodium Chloride came about because Sodium, a positively charged ion, has one electron in its outermost shell and Chlorine, a negatively charged ion, has seven electrons in its outmost shell. Sodium transfers the one electron to the Chlorine because in order for Sodium to have a full shell it would have needed seven more electrons to complete its shell. So instead in bonding with the Chlorine, its shell was completed and the ions were “happy”. 6. Johnny can’t find water on the periodic table because water is a molecule made up of two different atoms: hydrogen and oxygen. 7. The chemical formula for one water molecule is: H2O. H2O means that it took two hydrogen atoms to bond with one oxygen atom to create the water molecule. 8. The bond that is represented by the water molecule is a covalent bond. A covalent bond occurs when two atoms link together through sharing electrons. This occurs because atoms always want to have a full outer shell and the oxygen atom has only six electrons in its outer shell. In order to get a full shell, the oxygen atom links together with the two hydrogen atoms who have one electron a piece in the their outer shells and when bonded together all of the atoms have full outer shells. 9. a. Atomic Mass: H: 2 O: 16
b. Atomic Number: H:1 O:8
c. Number of Protons: H: 1 O:8
d. Number of Neutrons:H:0 O:8
e.