Module 2 part 1

1. Matter.

Question Number. 1. An atom with 3 free electrons in its outer shell is said to be.

Option A. pentavalent.

Option B. covalent.

Option C. trivalent.

Correct Answer is. trivalent.

Explanation. Number of electrons in the outer shell is called the valency - 1 = monovalent, 2 = divalent, 3 = trivalent etc.

Question Number. 2. What is the mass number of an element?.

Option A. Number of electrons and protons.

Option B. Number of neutrons and protons.

Option C. Number of electrons and neutrons.

Correct Answer is. Number of neutrons and protons.

Explanation. NIL.

Question Number. 3. What do you get when you add 2H₂ and O?.

Option A. H₂ O.

Option B. 2H₂ O.

Option C. 2H₂ O₂ .

Correct Answer is. 2H₂ O.

Explanation. Water is molecules each made up of 2 hydrogen atoms and 1 oxygen atom. Here ther is 4 hydrogen atoms, and 2 oxygen atoms, so we can make 2 water molecules.

Question Number. 4. The splitting of a chemical compound is called.

Option A. bombardment.

Option B. synthesis.

Option C. analysis.

Correct Answer is. analysis.

Explanation. NIL.

Question Number. 5. What is the atomic number of an element?.

Option A. The number of neutrons in the atom.

Option B. The number of electrons in the atom.

Option C. The number of protons in the atom.

Correct Answer is. The number of protons in the atom.

Explanation. NIL. http://en.wikipedia.org/wiki/Atomic_number

Question Number. 6. An atom with 5 free electrons is said to be.

Option A. pentavalet.

Option B. covalent.

Option C. trivalent.

Correct Answer is. trivalent.

Explanation. 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 -5 = 3 = trivalent.

Question Number. 7. An atom consists of.

Option A. protons, neutron and electrons.

Option B. protons and electrons.

Option C. protons and neutrons.

Correct Answer is. protons, neutron and electrons.

Explanation. NIL.

Question Number. 8. The maximum number of electrons in the inner shell of an atom is.

Option A. 8.

Option B. 2.

Option C. 4.

Correct Answer is. 2.

Explanation. NIL.

Question Number. 9. The mass of a proton equals the mass of a.

Option A. neutron.

Option B. beta particle.

Option C. electron.

Correct Answer is. neutron.

Explanation. Mass of a proton = mass of a neutron (well, very nearly).

Question Number. 10. Catalysts.

Option A. speed up reactions.

Option B. speed up and slow down reactions.

Option C. slow down reactions.

Correct Answer is. speed up reactions.

Explanation. A catalyst speeds up reactions, an inhibitor slows down reaction.

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.

Question Number. 21. What form of heat is used to turn a solid into a liquid?.

Option A. specific heat.

Option B. coefficient of heat.

Option C. heat of fusion.

Correct Answer is. heat of fusion.

Explanation. Fusion' is another term for melting (as in fusion welding).

Question Number. 22. Change from solid to gas state without going through liquid state is called.

Option A. transformation.

Option B. sublimation.

Option C. state leap.

Correct Answer is. sublimation.

Explanation. Sublimation is when a solid vapourises without first melting.

Question Number. 23. What is the smallest particle of matter that can exist in nature?.

Option A. A molecule.

Option B. An isotope.

Option C. An atom.

Correct Answer is. An atom.

Explanation. An atom is the smallest particle of matter that can exist in nature.

Question Number. 24. A positive ion.

Option A. has extra electrons.

Option B. has missing electrons.

Option C. is a radioactive isotope.

Correct Answer is. has missing electrons.

Explanation. A positive ion is an atom with missing electrons.

Question Number. 25. The isotope of a carbon atom C14 to C12 will have.

Option A. same numbers of neutrons.

Option B. same numbers of protons.

Option C. same number of electrons.

Correct Answer is. same numbers of protons.

Explanation. An isotope is an atom with the same atomic number but different mass number. Atomic number is the number of protons. Mass number is the number of protons plus neutrons. Note: the number of electrons can differ from one atom to another (making ions).

Question Number. 26. If an atom has 2 protons, how many electrons will it have?.

Option A. 1.

Option B. 8.

Option C. 2.

Correct Answer is. 2.

Explanation. Since it is an 'atom' (and not an ion) it has the same number of electrons as protons.

Question Number. 27. A molecule with like atoms is said to be a.

Option A. neutroid.

Option B. compound.

Option C. element.

Correct Answer is. element.

Explanation. If only one type of atom is involved, it is an element.

Question Number. 28. Two elements in the same substance is said to be a.

Option A. mixture.

Option B. element.

Option C. compound.

Correct Answer is. compound.

Explanation. A compound is a substance formed by chemical reaction between 2 or more elements. A mixture could be 2 or more compounds. A tenuous question.

Question Number. 29. The number of protons in an atom is equal to the number of.

Option A. electrons.

Option B. neutrons.

Option C. mass number.

Correct Answer is. electrons.

Explanation. No. of protons = No. of electrons, or it is not an atom.

Question Number. 30. The charge of an electron is.

Option A. neutral.

Option B. negative.

Option C. positive.

Correct Answer is. negative.

Explanation. Electrons are negative.

Question Number. 31. A valance electron is an electron.

Option A. in the innermost shell.

Option B. in the outermost shell.

Option C. which is not within an atom.

Correct Answer is. in the outermost shell.

Explanation. The outer shell is the valence shell.

Question Number. 32. Molecules of unlike atoms are combined by their.

Option A. adhesive force.

Option B. magnetic force.

Option C. cohesive force.

Correct Answer is. adhesive force.

Explanation. Cohesion is the property that causes like substances to cling together (eg water molecules, forming raindrops - from 'cohesion' meaning to stick together). Adhesion is the property that causes unlike substances to stick together (eg the raindrops stick, or 'adhere to' a washing line).

Question Number. 33. What is the difference between hydrogen, deuterium and tritium?.

Option A. The number of electrons.

Option B. The number of protons.

Option C. The number of neutrons.

Correct Answer is. The number of neutrons.

Explanation. There are three isotopes of the element hydrogen: hydrogen, deuterium, and tritium. They each have one single proton (Z=1), but differ in the number of their neutrons. Hydrogen has no neutron, deuterium has one, and tritium has two neutrons.

Question Number. 34. The smallest material in the universe is.

Option A. an ion.

Option B. helium.

Option C. hydrogen.

Correct Answer is. hydrogen.

Explanation. Hydrogen is the smallest known element, having just 1 electron and 1 proton and no neutrons.

Question Number. 35. What is the atomic number of the element shown here?.

Option A. 7.

Option B. 3.

Option C. 4.

Correct Answer is. 3.

Explanation. The atomic number is the number of protons and is always the smallest number (and yes, the element shown is not possible).

Question Number. 36. What is the mass number of the element shown here?.

Option A. 4.

Option B. 5.

Option C. 9.

Correct Answer is. 5.

Explanation. The mass number is the number of protons + the number of neutrons and is always the biggest of the 2 numbers.

Question Number. 37. There are solids, liquids and gases present in the universe and every unit of theirs occupy some space. This is called.

Option A. matter.

Option B. compound.

Option C. mass.

Correct Answer is. matter.

Explanation. All material in space is known as matter. (All matter 'has' mass, but that is not what the question asks - what is it known as, not, what does it have).

Question Number. 38. An atom deficient of a valency electron is deficient.

Option A. of an electron in the outer shell.

Option B. of a neutron in the outer shell.

Option C. of an electron in the inner shell.

Correct Answer is. of an electron in the outer shell.

Explanation. The valency electrons are in the outer shell.

Question Number. 39. The maximum number of electrons in the second shell is.

Option A. 4.

Option B. 8.

Option C. 2.

Correct Answer is. 8.

Explanation. Try the formula '2n-squared', where 'n' is the shell number. In this case 2 * (2 * 2) = 8.

Question Number. 40. What does an oxygen atom consist of?.

Option A. Protons, neutrons and electrons.

Option B. Protons and electrons.

Option C. Protons and neutrons.

Correct Answer is. Protons, neutrons and electrons.

Explanation. All atoms have protons, neutrons and electrons (except hydrogen, which has no neutrons).

Question Number. 41. Surface molecular attraction between two different molecules is.

Option A. adhesive.

Option B. gravitational.

Option C. cohesive.

Correct Answer is. adhesive.

Explanation. Cohesion is the property that causes like substances to cling together (e.g. water molecules, forming raindrops - from 'cohesion' meaning to stick together). Adhesion is the property that causes unlike substances to stick together (e.g. the raindrops stick, or 'adhere to' a washing line).

Question Number. 42. The atomic mass number is the number of.

Option A. protons plus electrons.

Option B. neutrons plus electrons.

Option C. protons plus neutrons.

Correct Answer is. protons plus neutrons.

Explanation. Mass Number is the number of protons + neutrons.

Question Number. 43. A catalyst in a chemical reaction does what?.

Option A. Can either speed it up or slow it down.

Option B. Speeds it up.

Option C. Slows it down.

Correct Answer is. Speeds it up.

Explanation. Official definition of 'catalyst': A substance that increases the rate of a chemical reaction by reducing the activation energy, but which is left unchanged by the reaction.

Question Number. 44. What is the number of electrons in the inner-most shell of an atom?.

Option A. 4.

Option B. 8.

Option C. 2.

Correct Answer is. 2.

Explanation. The inner shell of an atom has 2 electrons.

Question Number. 45. What form of heat is used to turn a solid into a gas?.

Option A. Sensible heat.

Option B. Specific heat.

Option C. Latent heat.

Correct Answer is. Latent heat.

Explanation. To change any state, the heat required is called 'latent heat'.

Question Number. 46. The heat required to change a liquid to a gas at constant temperature is the heat of.

Option A. fusion.

Option B. condensation.

Option C. vaporisation.

Correct Answer is. vaporisation.

Explanation. The heat required to turn a liquid into a gas (vaporise) is called the 'latent heat of vaporisation'.

Question Number. 47. An atom with a full outer shell is.

Option A. practically inert.

Option B. a good insulator.

Option C. a good conductor.

Correct Answer is. practically inert.

Explanation. An atom with a full outer shell is practically inert.

Question Number. 48. An element with a full valence shell is.

Option A. very reactive.

Option B. good conductor.

Option C. inert.

Correct Answer is. inert.

Explanation. An element with a full valence shell is inert.

Question Number. 49. A substance of two or more different atoms is.

Option A. a neutrino.

Option B. an isotope.

Option C. a chemical compound.

Correct Answer is. a chemical compound.

Explanation. A compound is two or more different atoms.

Question Number. 50. An atom with 5 electrons in its outer shell is.

Option A. trivalent.

Option B. pentavelent.

Option C. covalent.

Correct Answer is. trivalent.

Explanation. Valency is the number of electrons in the outer shell (up to 4) or 8 minus the number of electrons in the outer shell (over 4).