Unit 1 Review Questions

The nucleus of most atoms is made up of:
1. protons and electrons
2. protons and neutrons
3. neutrons and electrons
4. electrons and protons
The laws of electrostatics consistently demonstrate that opposite charges:
1. destroy one another
2. attract
3. repel
The charge and mass number of a proton are:
1. charge = +1, Mass number = 0
2. charge = -1, Mass number = 0
3. charge = 0, Mass number = 1
4. charge = +1, Mass number = 1
The charge and mass number of an electron are:
1. charge = +1, Mass number = 0
2. charge = -1, Mass number = 0
3. charge = 0, Mass number = 1
4. charge = +1, Mass number = 1
The charge and mass number of a neutron are:
1. charge = +1, Mass number = 0
2. charge = -1, Mass number = 0
3. charge = 0, Mass number = 1
4. charge = +1, Mass number = 1
Most of the mass of the atom can be found in the:
1. electron cloud
2. nucleus
3. electrons
4. charges
Which of the following descriptions does not apply to the nucleus?
1. Very dense
2. Mostly empty space
3. Positively charged
4. Very small
Of the basic atomic particles, the one that would be attracted to a negatively charged metallic plate is the:
1. proton
2. neutron
3. electron
The mass number of an atom is determined by:
1. adding the protons and electrons
2. adding the neutrons and electrons
3. adding the neutrons and protons
4. the number of protons only
The _______________ constitute(s) most of the volume of an atom.
1. protons
2. neutrons
3. nucleus
4. electron cloud
The atomic number of an element is equal to:
1. the number of protons in the atom
2. the number of neutrons in the atom
3. the number of protons plus the number of neutrons
4. the number of protons plus the number of electrons
How many electrons, neutrons and protons would be found in an atom of carbon-14 (atomic number 6)?
1. 6 electrons, 6 neutrons, 6 protons
2. 6 electrons, 6 neutrons, 8 protons
3. 8 electrons, 8 neutrons, 6 protons
4. 6 electrons, 8 neutrons, 6 protons
How many electrons would be found in an atom of oxygen (atomic number 8)?
1. 2
2. 4
3. 6
4. 8
An element with nine protons in every atom must:
1. have nine neutrons as well
2. be fluorine
3. have a mass number of nine
4. be unstable
What is the neutron-proton ratio for nitrogen-14?
1. 14:1
2. 2:1
3. 1:2
4. 7:2
5. 1:1
There are three isotopes of the element argon: argon-36, argon-38 and argon-40. Theses isotopes differ from one another in:
1. their atomic number
2. their number of electrons
3. their number of protons
4. their number of neutrons
How many atoms are there in one mole of any element?
1. 2.06 x 10^-3
2. 6.022 x 10^-23
3. 6.022 x 10²³
4. 12.0
How many grams of naturally occurring phophorus must one have in order to have one mole of phosphorus?
1. 15 grams
2. 30.97 grams
3. 6.02 x 10²³ grams
4. 6.02 x 10^-23 grams
The atomic number of hydrogen is 1. The atomic number of helium is two. Compared to a mole of hydrogen, a mole of helium can be said to have:
1. the same number of particles as a mole of hydrogen
2. half as many particles as a mole of hydrogen
3. twice as many particles as a mole of hydrogen
4. two particles
How many neutrons are there in an atom of hydrogen-3?
1. 0
2. 1
3. 2
4. 3
What is the approximate mass in grams of 3.011 x 10²³ atoms of chromium (atomic #24)?
1. 24 grams
2. 52 grams
3. 26 grams
4. 12 grams
How many moles of magnesium are there in 48.62 grams of magnesium?
1. 0.5000 moles
2. 2.000 moles
3. 3.01 x 10²³ moles
4. 6.02 x 10²³ moles
What is the mass in grams of 3.50 moles of boron (at #5)?
1. 37.8 grams
2. 3.09 grams
3. 0.324 grams
4. 2.11 x 10²⁴ grams
Isotope Mass number Atomic number Protons Neutrons Electrons
Scandium-45
1. The blanks, respectively, would be filled: 21, 45, 21, 21, 24
2. The blanks, respectively, would be filled: 45, 21, 21, 24, 21
3. The blanks, respectively, would be filled: 21, 45, 24, 21, 21
4. The blanks, respectively, would be filled: 24, 21, 45, 21, 21
Isotope Mass number Atomic number Protons Neutrons Electrons
_______________-27 13
1. The blanks, respectively, would be filled: aluminum, 27, 13, 13, 14
2. The blanks, respectively, would be filled: cobalt, 40, 27, 13, 27
3. The blanks, respectively, would be filled: aluminum, 27, 13, 14, 13
4. The blanks, respectively, would be filled: silicon, 27, 14, 13, 13
A process in which a very heavy nucleus splits into more-stable nuclei of intermediate mass.
1. nuclear fusion
2. nuclear fission
3. radioactive decay
4. a chain reaction
5. radiocarbon dating
An electron emitted from the nucleus during some kinds of radioactive decay is known as:
1. An alpha (a) particle
2. A beta (b) particle
3. A positron
4. A gamma ray
An alpha (a) particle is essentially a ____________________ nucleus.
1. hydrogen
2. uranium
3. carbon-12
4. helium
5. plutonium
Gamma (g) rays are:
1. neutrons
2. protons
3. electrons
4. pure energy waves
Very large nuclei tend to be unstable because of the:
1. repulsive forces between electrons
2. attraction of electrons for the positively charged nucleus
3. repulsive forces between neutrons
4. repulsive forces between protons
5. attraction of protons for neutrons
For the most common types of radioactive decay, the order of mass from heaviest to lightest is:
1. gamma, alpha, beta
2. beta, alpha, gamma
3. beta, gamma, alpha
4. alpha, beta, gamma
For the most common types of radioactive decay, the order of least penetrating to human tissue, to most penetrating to human tissue is:
1. gamma, alpha, beta
2. alpha, beta, gamma
3. beta, gamma, alpha
4. gamma, beta, alpha
For the most common types of radioactive decay, the order of least dangerous to most dangerous is:
1. gamma, alpha, beta
2. alpha, beta, gamma
3. beta, gamma, alpha
4. gamma, beta, alpha
In nuclear reactions:
1. small amount of mass are converted to large amounts of mass
2. large amount of energy are converted to small amount of mass
3. small amounts of mass are converted to large amount of energy
4. mass and energy are destroyed
Compared to chemical reactions, nuclear reactions produce:
1. proportionally far less energy
2. proportionally far more energy
3. fewer changes in the nucleus
4. more vegetables
Which of the following statements is true?
1. All man-made isotopes are radioactive
2. Some man-made isotopes are radioactive
3. None of the man-made isotopes are radioactive
4. bismuth, atomic #83
Which of the following statements is true?
1. All naturally occurring isotopes are radioactive
2. Some naturally occurring isotopes are radioactive
3. No naturally occurring isotopes are radioactive
4. bismuth, atomic #83
Identify the missing particle in the following nuclear reaction:

²³⁹₉₃Np ----> ²³⁹₉₄Pu + _____
1. ¹₀n
2. ⁰₁e
3. ⁰_-1e
4. ¹₁H
Identify the missing particle in the following nuclear reaction:

³₂He + ³₂He ----> 2 ¹₁H + _____
1. ⁴₂He
2. ⁵₃Li
3. ¹₂He
4. ¹₁H
Identify the missing particle in the following nuclear reaction:

¹₀n + ²³⁵₉₂U ----> 2 ¹₀n + _____ + ¹³⁷₅₂Te
1. ⁴₂He
2. ⁹⁷₃₈Sr
3. ⁹⁶₄₀Zr
4. ⁹⁷₄₀Zr

Isotope	Mass number	Atomic number	Protons	Neutrons	Electrons
Scandium-45

Unit 1 Review Questions

Multiple-choice exercise