Understanding Concepts
• 6. Which element has a full outermost energy level containing only 2 electrons?
• a) oxygen b) hydrogen c) fluorine
• d) helium
• Answer: d) Helium
• 7. Which (of the following) describes what happens when an atom becomes an ion with a 2- charge?
• Answer: c) the atom gains 2 electrons
• 8. The properties of ductility and malleability are associated with which type of bonds?
• a) ionic b) covalent c) metallic d) none of the above
• Answer: c) metallic
• 9. In which area of the periodic table do you find elements whose atoms easily gain electrons?
• Answer: c) on the right side
• 10. What type of element tends to lose electrons when it forms bonds?
• A) metal b) metalloid c) nonmetal d) noble gas
• Answer: a) metals
Short Answers
• 12. List two properties of covalent compounds.
• Answers could include:
• - a low melting point,
• - a low boiling point,
• - brittle when solid at room temp.
• 13. Explain why an iron ion is attracted to a sulfide ion but NOT to a zinc ion?
• Answer: iron and zinc are metals that tend to lose electrons , thus becoming positively charged. They would repel each other.
• Sulfide ion is negatively charge sulfur atom that gained electron, so is attracted to a positively charge atom such as iron
• 14. Using knowledge of valence electrons, explain why carbon is an element in so many different molecules.
• Carbon has 4 valence electrons, therefore can have 4 bonds, including other carbon atoms. This is the most bonding possibilities. Usually atoms with less than 4 valence electrons give up electrons, and may only have one bond.
• 15. Three types of bonds:
• Ionic - lose/gain electrons
• Covalent - share electrons
• Metallic - electrons can move between ions within a metal
Critical Thinking
• 17. Types of bonding of these pairs:
• A) zinc + zinc = metallic
• B) oxygen + nitrogen = covalent
• C) phosphorus and oxygen = covalent
• D) magnesium and chlorine = ionic
• 18. Dots & bonds
• A) sulfur (S); 6 dots, 2 bonds
• B) nitrogen (N); 5 dots, 3
• C) neon (Ne); 8 dots, 0 bonds
• D) iodine (I); 7 dots, 1 bond
• E) silicon (Si); 4 dots, 4 bonds
• 19. What type of bond does the picture of a hammer is hitting a white, solid object with little parts appearing on the table represent.?
• Answer: The substance is brittle, and is breaking into tiny pieces, therefore is an ionic bond.
Math in Science
• 20.Electrons gained/loss and charge
• Answers:
• A) calcium (Ca); lose 2 e-; 2 +
• B) phosphorus (P); gain 3e-; 3 -
• C) bromine (Br); gain 1e-; 1-
• D) sulfur (S); gain 2e-; 2 -
Interpreting Graphics
• 21. The metal band near the eraser is the part of the pencil where metallic bonds are formed.
• 23. Two differences between the properties of the parts of the pencil are:
• Answer: The metallically bonded part of the pencil is shiny, can be bent without breaking, and is hard in texture;
• The covalently bonded parts are not shiny, will break when bent, and are softer. Example: eraser, graphite, wood