MODULE 3 PART 1.2

Question Number. 11. If the outer shell of an atom is full the the element is.
Option A. unstable / reactive.
Option B. a good conductor.
Option C. practically inert.
Correct Answer is. practically inert.
Explanation. NIL.




Question Number. 12. Molecules of the same compound are held together by.
Option A. cohesive forces.
Option B. adhesive forces.
Option C. gravitational forces.
Correct Answer is. cohesive forces.
Explanation. Cohesion is the property that causes like substances to cling together (eg water molecules, forming raindrops). Adhesion is the property that causes unlike substances to stick together (eg the raindrops stick on a washing line).




Question Number. 13. Oxygen has a valency of.
Option A. 2.
Option B. 6.
Option C. 8.
Correct Answer is. 2.
Explanation. Oxygen has 6 electrons in its outer shell. The valency is the number of electrons in the outer shell if that number is 4 or less. If there are more than 4 electrons, the valency is 8 minus the number of electrons. In this case 8 - 6 = 2.




Question Number. 14. The further from the nucleus the shells are in an atom.
Option A. the shells retain the same spacing from each other.
Option B. the closer the shells get to each other.
Option C. the further the shells get from each other.
Correct Answer is. the further the shells get from each other.
Explanation. The gap between the 'energy levels' reduces, but the physical gap increases slightly. http://www.1stardrive.com/solar/chem.htm




Question Number. 15. What determines an element's identity?.
Option A. The number of neutrons.
Option B. The number of electrons.
Option C. The number of protons.
Correct Answer is. The number of protons.
Explanation. NIL. http://en.wikipedia.org/wiki/Atomic_number




Question Number. 16. An isotope of an element will have more/less _________ than usual.
Option A. electrons.
Option B. neutrons.
Option C. protons.
Correct Answer is. neutrons.
Explanation. NIL. http://en.wikipedia.org/wiki/Isotope




Question Number. 17. The smallest part of an element is.
Option A. a compound.
Option B. an atom.
Option C. a molecule.
Correct Answer is. an atom.
Explanation. NIL.




Question Number. 18. The nucleus of an atom contains.
Option A. protons and electrons.
Option B. protons and neutrons.
Option C. electrons and neutrons.
Correct Answer is. protons and neutrons.
Explanation. NIL.




Question Number. 19. What is atomic mass?.
Option A. Number of neutrons.
Option B. Number of protons plus the number of neutrons.
Option C. Number of protons.
Correct Answer is. Number of protons plus the number of neutrons.
Explanation. NIL.




Question Number. 20. A solid melted into a liquid will take up.
Option A. less space.
Option B. the same amount of space.
Option C. more space.
Correct Answer is. less space.
Explanation. When a solid melts, its volume decreases - and then begins to increase again as the temperature of the liquid rises.