AP Chemistry Review - Atoms, Molecules and Ions

By knowing the number of electrons in a neutral atom, you should also be able to determine
1. the number of neutrons in the neutral atom
2. the number of protons in the neutral atom
3. the atomic number of the neutral atom
4. the mass of the neutral atom
5. two of these
The apparatus pictured here helped to determine:
1. the existence of electrons
2. that atoms are mostly empty space
3. that energy travels at the speed of light
4. that electrons have mass
5. that mass and energy are related by E=mc²
Which of the following arrangements represent ions?

1) 12 protons, 12 neutrons, 11 electrons
2) 12 protons, 11 neutrons, 12 electrons
3) 11 protons, 12 neutrons, 12 electrons
4) 11 protons, 12 neutrons, 11 electrons
5) 12 protons, 12 neutrons, 12 electrons
1. 1 and 2
2. 1, 3, and 4
3. 1 and 3
4. 2 and 3
5. all of these are ions
Which of the following arrangements represent different isotopes of the same element?

1) 12 protons, 11 neutrons, 12 electrons
2) 11 protons, 12 neutrons, 11 electrons
3) 10 protons, 12 neutrons, 12 electrons
4) 11 protons, 12 neutrons, 10 electrons
5) 12 protons, 12 neutrons, 12 electrons
1. 1 and 5
2. 2 and 4
3. 2, 3, 4 and 5
4. all of these qualify
5. None of these qualify
The average mass of a magnesium atom is 24.31. If you were able to select and measure a single atom of magnesium, the chance that you would select an atom of mass 24.31 is about:
1. 0%
2. 0.31%
3. 24.31%
4. greater than 50%
5. 100%
How many oxygen atoms are there in one formula unit of Al₂(SO₄)₃?
1. 3
2. 4
3. 7
4. 12
5. 24
Which of the following is named incorrectly?
1. H₂CO₂ : carbonous acid
2. HClO₂ : chlorous acid
3. H₂SO₄ : sulfuric acid
4. HClO : hydrochlorous acid
5. H₃PO₃ : phosphorous acid
The name for the compound NaHSO₄ is:
1. sodium hydrogen sulfate
2. sodium persulfate
3. sodium bisulfate
4. two of these are correct
5. none of these is correct
Which of following is not true of the carbon-14 atom?
1. It has six protons
2. It has an average mass of 12.011 amu.
3. It has six electrons
4. It has eight neutrons
5. It is the less common than carbon-12
Of the following elements, the one that forms cations with varying positive charges is:
1. iron, Fe
2. sodium, Na
3. aluminum, Al
4. strontium, Sr
5. nitrogen, N
The correct name for MgO₂ is:
1. magnesium(II) oxide
2. magnesium(IV) oxide
3. magnesium peroxide
4. magnesium oxide
5. magnesium(IV) peroxide
A particle with 15 protons and 18 electrons would be symbolized as:
1. Ar
2. Ar^3-
3. P^3-
4. P³⁺
5. Ar³⁺
Which of the following statements is incorrect?:
1. metals generally form cations
2. nonmetals are generally poor conductors of electricity
3. metals are malleable
4. nonmetals are generally brittle
5. metalloids are metals with some nonmetallic characteristics
Which of these is the correct number of particles in the nuclide above?
1. 34 protons, 79 neutrons, 2 electrons
2. 34 protons, 45 neutrons, 32 electrons
3. 34 protons, 45 neutrons, 2 electrons
4. 34 protons, 45 neutrons, 36 electrons
5. 34 protons, 113 neutrons, 36 electrons
Which of the above have equal numbers of neutrons?
1. I, II and III
2. II and III
3. I and V
4. I and IV
5. II, III and IV
Ions are formed in chemical reactions by:

1. Gaining electrons
2. Losing electrons
3. Gaining protons
4. Losing protons
5. All of these
1. 1 and 2 are correct
2. 3 and 4 are correct
3. 5 is correct
4. 1 and 3 are correct
5. 2 and 4 are correct
The number of errors contained in the table below is:
Nuclide protons neutrons electrons mass
sodium-23 11 12 11 23
Cobalt-59 27 22 27 59
Tungsten-184 74 110 184 184
fluorine-19 10 9 10 19
1. one
2. two
3. three
4. four
5. five
The element hafnium (Hf) has five stable isotopes. The correct number of nuclear particles in an atom of hafnium-178 is:
1. 72 protons, 178 neutrons
2. 72 protons, 72 electrons
3. 106 protons, 72 neutrons
4. 72 protons, 106 neutrons
5. 72 protons, 106 neutrons, 72 electrons
J.J. Thomson's model of the atom can be summarized with the visual image of:
1. planets orbiting the sun
2. plum pudding
3. bees around a hive
4. a small central nucleus and an electron cloud
5. none of the above
A particle X contains 10 electrons, seven neutrons and has a net charge of 3-. The particle is:
1. a nitride ion
2. obviously polyatomic
3. an oxide ion
4. a neon ion
5. none of these are correct

Nuclide	protons	neutrons	electrons	mass
sodium-23	11	12	11	23
Cobalt-59	27	22	27	59
Tungsten-184	74	110	184	184
fluorine-19	10	9	10	19