Unit 3 Test
Multiple Choice
Please select the correct response for the following questions.
1. What is the smallest part of all matter called? (1 point) *
a. Element
b. Atom
c. Molecule
d. Compound
2. Which of the subatomic particles is negative? (1 point)
a. Nucleus
b. Neutron
c. Proton
d. Electron
3. Who provided the first evidence that atoms contain subatomic particles? (2 points) *
a. Thomson
b. Rutherford
c. Dalton
d. Newton
4. When two fluorine atoms share a pair of electrons, the bond that forms is a(n) _____________. (2 points) *
a. Double bond
b. Polar covalent bond
c. Nonpolar covalent bond
d. Ionic bond
5. How would you find the number of neutrons in an atom? (2 points) *
a. Atomic number - mass number
b. Mass number - atomic number
c. Electrons + protons
d. Protons - electrons
6. Isotopes of an element have the same atomic number, but different mass numbers because they have different numbers of ________________. (2 points) *
a. Electrons
b. Protons
c. Neutrons
d. Subatomic particles
7. Electrons in the first energy level of an atom, (2 points) *
a. Have no energy
b. Have the lowest possible energy
c. Have the highest possible energy
d. Are unstable
8. An element that is shiny and easily conducts electric currents is called a ________________. (2 points) *
a. Nonmetal
b. Metal
c. Transition metal
d. Noble gas
9. Elements that have the same number of valence electrons are in the same __________ on the periodic table. (2 points) *
a. Group
b. Period
c. Row
d. Section
10. Which list of elements contains only metalloids? (2 points) *
a. Gallium, germanium, and arsenic
b. Silicon and germanium
c. Aluminum, silicon, and phosphorus
d. Phosphorus and arsenic
11. In the Rutherford experiment, why weren’t all the alpha particles deflected? (3 points) *
a. The particles have a positive charge.
b. The particles were too small.
c. The nucleus was too small compared to the atom as a whole.
d. The beam was attracted to a positively charged plate.
12. What does an electron cloud represent? (3 points)
a. The location of electrons around the nucleus
b. The location of electrons within the nucleus
c. The location of electrons in the universe
d. The location of the nucleus
Using the periodic table, find the element (1 point each)
13. What element is in period 2 group 5A (15)? *
Your answer
14. What element is in period 4 group 2A (2)? *
Your answer
15. What element is in period 6 group 1B (11)? *
Your answer
Name the following compounds (1 point each):
16. KCl *
Your answer
17. NO *
Your answer
18. H2O *
Your answer
19. Mg(OH)2 *
Your answer
Open Ended
Please answer the following question in complete sentences.
20. Why isn’t it possible for an atom to have a mass number of 15 and an atomic number of 18? (4 points) *
1. b. Atom
2. d. Electron
3. a. Thomson
4. c. Nonpolar covalent bond
5. b. Mass number - atomic number
6. c. Neutrons
7. b. Have the lowest possible energy
8. b. Metal
9. a. Group
10. b. Silicon and germanium
11. c. The nucleus was too small compared to the atom as a whole.
12. a. The location of electrons around the nucleus
13. Nitrogen (N)
14. Calcium (Ca)
15. Gold (Au)
16. Potassium chloride
17. Nitric oxide
18. Water
19. Magnesium hydroxide
20. An atom's atomic number is determined by the number of protons it has, while the mass number is determined by the sum of protons and neutrons. Since the atomic number of an atom cannot change, an atom with an atomic number of 18 can never have a mass number of 15. This is because the mass number is always equal to or greater than the atomic number due to the presence of neutrons.
1. The correct response is b. Atom. To determine the smallest part of all matter, you need to understand that matter is made up of atoms, which are the basic building blocks of all elements. To get this answer, you should have knowledge of basic chemistry and atomic structure.
2. The correct response is d. Electron. To know which subatomic particle is negative, you should be familiar with the three main subatomic particles: protons, neutrons, and electrons. Protons have a positive charge, neutrons have no charge, and electrons have a negative charge.
3. The correct response is a. Thomson. To identify who provided the first evidence that atoms contain subatomic particles, you need to know about the experiments conducted by various scientists. In this case, Thomson's cathode ray tube experiment provided evidence for the existence of electrons within atoms.
4. The correct response is c. Nonpolar covalent bond. To determine which type of bond forms when two fluorine atoms share a pair of electrons, you need to be familiar with chemical bonding. Fluorine is a nonmetal, and when two nonmetal atoms share electrons equally, a nonpolar covalent bond is formed.
5. The correct response is b. Mass number - atomic number. To find the number of neutrons in an atom, you can subtract the atomic number (which represents the number of protons) from the mass number (which represents the total number of protons and neutrons).
6. The correct response is c. Neutrons. To understand why isotopes of an element have the same atomic number but different mass numbers, you need to know about the composition of isotopes. Isotopes are atoms of the same element that have different numbers of neutrons.
7. The correct response is b. Have the lowest possible energy. To determine the energy level of electrons in the first energy level of an atom, you should have knowledge of the energy levels or shells within an atom. Electrons in the first energy level have the lowest possible energy.
8. The correct response is b. Metal. To identify an element that is shiny and easily conducts electric currents, you should have knowledge of the properties of metals. Metals are good conductors of electricity and heat and usually have a shiny appearance.
9. The correct response is a. Group. To determine which category elements belong to if they have the same number of valence electrons, you need to understand the periodic table's structure. Elements in the same group share similar properties because they have the same number of valence electrons.
10. The correct response is b. Silicon and germanium. To identify a list of elements that contains only metalloids, you should know the properties and locations of metalloids on the periodic table. Silicon and germanium are examples of metalloids.
11. In the Rutherford experiment, the correct response is c. The nucleus was too small compared to the atom as a whole. To explain why not all the alpha particles were deflected in the Rutherford experiment, you need to understand the experimental setup and the concept of the atom's structure. In Rutherford's gold foil experiment, most alpha particles passed through the gold foil because the nucleus was much smaller compared to the atom's overall size.
12. The correct response is a. The location of electrons around the nucleus. To understand what an electron cloud represents, you need knowledge of atomic structure. The electron cloud represents the region or space around the nucleus where electrons are likely to be found.
13. Using the periodic table, the element in period 2 group 5A (15) is nitrogen (N).
14. Using the periodic table, the element in period 4 group 2A (2) is beryllium (Be).
15. Using the periodic table, the element in period 6 group 1B (11) is copper (Cu).
16. KCl represents potassium chloride.
17. NO represents nitrogen monoxide.
18. H2O represents water.
19. Mg(OH)2 represents magnesium hydroxide.
20. It is not possible for an atom to have a mass number of 15 and an atomic number of 18 because the mass number represents the total number of protons and neutrons in an atom, while the atomic number represents the number of protons. Since the atomic number of an element determines its identity, an atomic number of 18 would correspond to the element Argon (Ar), which has 18 protons. However, an atom with a mass number of 15 would need to have 15 protons and 15 neutrons, which does not match the atomic number. Therefore, an atom cannot have these specific values for mass number and atomic number simultaneously.