Download Chemistry UNIT 3 Test

Chemistry UNIT 3 Test
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____
1. What does the number 16 in the name Oxygen-16 represent?
a. the atomic number
c. the sum of the protons and electrons
b. the mass number
d. twice the number of protons
____
2. What is the shape of the 2s atomic orbital?
a. sphere
b. dumbbell
c. bar
d. two perpendicular dumbbells
____
3. The particles that are found in the nucleus of an atom are ____.
a. neutrons and electrons
c. protons and neutrons
b. electrons only
d. protons and electrons
____
4. The smallest particle of an element that retains the properties of that element is a(n) ____.
a. atom
c. proton
b. electron
d. neutron
____
5. Which of the following statements is NOT true?
a. Protons have a positive charge.
b. Electrons are negatively charged and have a mass of 1 amu.
c. The nucleus of an atom is positively charged.
d. Neutrons are located in the nucleus of an atom.
____
6. As a consequence of the discovery of the nucleus by Rutherford, which model of the atom is thought to be
true?
a. Protons, electrons, and neutrons are evenly distributed throughout the volume of the atom.
b. The nucleus is made of protons, electrons, and neutrons.
c. Electrons are distributed around the nucleus and occupy almost all the volume of the atom.
d. The nucleus is made of electrons and protons.
____
7. An element has an atomic number of 76. The number of protons and electrons in a neutral atom of the
element are ____.
a. 152 protons and 76 electrons
c. 38 protons and 38 electrons
b. 76 protons and 0 electrons
d. 76 protons and 76 electrons
____
8. What is the electron configuration of potassium?
a. 1s 2s 2p 3s 3p 4s
c. 1s 2s 3s 3p 3d
b. 1s 2s 2p 3s 3p
d. 1s 2s 2p 3s 3p 4s
____
9. Stable electron configurations are likely to contain ____.
a. filled energy sublevels
b. fewer electrons than unstable configurations
c. unfilled s orbitals
d. electrons with a clockwise spin
____ 10. What types of atomic orbitals are in the third principal energy level?
a. s and p only
c. s, p, and d only
b. p and d only
d. s, p, d, and f
____ 11. If three electrons are available to fill three empty 2p atomic orbitals, how will the electrons be distributed in
the three orbitals?
a. one electron in each orbital
b. two electrons in one orbital, one in another, none in the third
c. three in one orbital, none in the other two
d. Three electrons cannot fill three empty 2p atomic orbitals.
____ 12. What is the next atomic orbital in the series 1s, 2s, 2p, 3s, 3p?
a. 2d
c. 3f
b. 3d
d. 4s
____ 13. What is the maximum number of orbitals in the d sublevel?
a. 2
c. 4
b. 3
d. 5
____ 14. According to the aufbau principle, ____.
a. an orbital may be occupied by only two electrons
b. electrons in the same orbital must have opposite spins
c. electrons enter orbitals of highest energy first
d. electrons enter orbitals of lowest energy first
____ 15. Who was the man who lived from 460B.C.–370B.C. and was among the first to suggest the idea of atoms?
a. Atomos
c. Democritus
b. Dalton
d. Thomson
____ 16. In the Bohr model of the atom, an electron in an orbit has a fixed ____.
a. position
c. energy
b. color
d. size
____ 17. The mass number of an element is equal to ____.
a. the total number of electrons in the nucleus
b. the total number of protons and neutrons in the nucleus
c. less than twice the atomic number
d. a constant number for the lighter elements
____ 18. Which of the following is true about subatomic particles?
a. Electrons are negatively charged and are the heaviest subatomic particle.
b. Protons are positively charged and the lightest subatomic particle.
c. Neutrons have no charge and are the lightest subatomic particle.
d. The mass of a neutron nearly equals the mass of a proton.
____ 19. Isotopes of the same element have different ____.
a. numbers of neutrons
c. numbers of electrons
b. numbers of protons
d. atomic numbers
____ 20. How do the isotopes hydrogen-1 and hydrogen-2 differ?
a. Hydrogen-2 has one more electron than hydrogen-1.
b. Hydrogen-2 has one neutron; hydrogen-1 has none.
c. Hydrogen-2 has two protons; hydrogen-1 has one.
d. Hydrogen-2 has one proton; hydrogen-1 has none.
____ 21. The atomic number of an element is the total number of which particles in the nucleus?
a. neutrons
c. electrons
b. protons
d. protons and electrons
____ 22. Which hypothesis led to the discovery of the proton?
a. When a neutral hydrogen atom loses an electron, a positively-charged particle should
remain.
b. A proton should be 1840 times heavier than an electron.
c. Cathode rays should be attracted to a positively-charged plate.
d. The nucleus of an atom should contain neutrons.
____ 23. All atoms of the same element have the same ____.
a. number of neutrons
c. mass numbers
b. number of protons
d. mass
____ 24. Which of the following was originally a tenet of Dalton's atomic theory, but had to be revised about a century
ago?
a. Atoms are tiny indivisible particles.
b. Atoms of the same element are identical.
c. Compounds are made by combining atoms.
d. Atoms of different elements can combine with one another in simple whole number ratios.
____ 25. How many energy sublevels are in the second principal energy level?
a. 1
c. 3
b. 2
d. 4
____ 26. Dalton's atomic theory included which idea?
a. All atoms of all elements are the same size.
b. Atoms of different elements always combine in one-to-one ratios.
c. Atoms of the same element are always identical.
d. Individual atoms can be seen with a microscope.
____ 27. In Bohr's model of the atom, where are the electrons and protons located?
a. The electrons move around the protons, which are at the center of the atom.
b. The electrons and protons move throughout the atom.
c. The electrons occupy fixed positions around the protons, which are at the center of the
atom.
d. The electrons and protons are located throughout the atom, but they are not free to move.
____ 28. What is the number of electrons in the outermost energy level of a carbon atom?
a. 2
c. 6
b. 4
d. 8
____ 29. What unit is used to measure weighted average atomic mass?
a. amu
c. angstrom
b. gram
d. nanogram
____ 30. The sum of the protons and neutrons in an atom equals the ____.
a. atomic number
c. atomic mass
b. nucleus number
d. mass number
____ 31. How does the energy of an electron change when the electron moves closer to the nucleus?
a. It decreases.
c. It stays the same.
b. It increases.
d. It doubles.
____ 32. If the spin of one electron in an orbital is clockwise, what is the spin of the other electron in that orbital?
a. zero
c. counterclockwise
b. clockwise
d. both clockwise and counterclockwise
____ 33. The nucleus of an atom is ____.
a. the central core and is composed of protons and neutrons
b. positively charged and has more protons than neutrons
c. negatively charged and has a high density
d. negatively charged and has a low density
____ 34. What is the maximum number of d orbitals in a principal energy level?
a. 1
c. 3
b. 2
d. 5
____ 35. How is the number of neutrons in the nucleus of an atom calculated?
a. Add the number of electrons and protons together.
b. Subtract the number of electrons from the number of protons.
c. Subtract the number of protons from the mass number.
d. Add the mass number to the number of electrons.