Unit 2 Quiz: Elements, Atoms, And Ions

1. The nucleus of an atom contains protons and neutrons ________________

The statement "The nucleus of an atom contains protons and neutrons" is true. The nucleus is the central part of an atom, and it contains positively charged protons and neutral neutrons. These subatomic particles are tightly packed together in the nucleus, while negatively charged electrons orbit around the nucleus in electron shells. The number of protons determines the atomic number of an element, while the total number of protons and neutrons determines the atomic mass.

Explanation

The statement "The nucleus of an atom contains protons and neutrons" is true. The nucleus is the central part of an atom, and it contains positively charged protons and neutral neutrons. These subatomic particles are tightly packed together in the nucleus, while negatively charged electrons orbit around the nucleus in electron shells. The number of protons determines the atomic number of an element, while the total number of protons and neutrons determines the atomic mass.

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2. Chlorine has the atomic number of 17 _____________

Chlorine has the atomic number of 17, which means it has 17 protons in its nucleus. The atomic number determines the element's identity, and in the case of chlorine, it is represented by the symbol Cl. Therefore, the statement "Chlorine has the atomic number of 17" is true.

Explanation

Chlorine has the atomic number of 17, which means it has 17 protons in its nucleus. The atomic number determines the element's identity, and in the case of chlorine, it is represented by the symbol Cl. Therefore, the statement "Chlorine has the atomic number of 17" is true.

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3. A chart containing all of the known elements arranged in an organized fashion is called the periodic table ______________

The correct answer is "True." The explanation is that a chart containing all of the known elements arranged in an organized fashion is indeed called the periodic table.

Explanation

The correct answer is "True." The explanation is that a chart containing all of the known elements arranged in an organized fashion is indeed called the periodic table.

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4. Nonmetals can be pulled into wires and conduct electricity. _______________

No; it is metals that can be pulled into wires and conduct electricity.

Explanation

No; it is metals that can be pulled into wires and conduct electricity.

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6. Nitrogen, oxygen and hydrogen exist as diatomic molecules ________________.

Nitrogen, oxygen, and hydrogen exist as diatomic molecules because they naturally combine with themselves to form stable molecules. Nitrogen (N2), oxygen (O2), and hydrogen (H2) all have two atoms bonded together, which makes them more stable and less reactive than if they were single atoms. This diatomic nature is a result of the elements' electron configurations and their tendency to achieve a full outer shell of electrons through bonding.

Explanation

Nitrogen, oxygen, and hydrogen exist as diatomic molecules because they naturally combine with themselves to form stable molecules. Nitrogen (N2), oxygen (O2), and hydrogen (H2) all have two atoms bonded together, which makes them more stable and less reactive than if they were single atoms. This diatomic nature is a result of the elements' electron configurations and their tendency to achieve a full outer shell of electrons through bonding.

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7. The formula for the compound containing Ba²⁺ and O^2- is BaO _________.

The formula for the compound containing Ba2+ and O2- is BaO because Ba2+ has a charge of +2 and O2- has a charge of -2. In order for the compound to be electrically neutral, the charges must balance out. Therefore, one Ba2+ ion combines with one O2- ion to form BaO.

Explanation

The formula for the compound containing Ba2+ and O2- is BaO because Ba2+ has a charge of +2 and O2- has a charge of -2. In order for the compound to be electrically neutral, the charges must balance out. Therefore, one Ba2+ ion combines with one O2- ion to form BaO.

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10. A chemical formula describes the shapes of the compound

A chemical formula describes the chemical composition of the compound.

Explanation

A chemical formula describes the chemical composition of the compound.

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11. In an ionic compound, both anions and cations must be present to form a molecule. ________

In an ionic compound, both anions and cations must be present to form a molecule. This is because an ionic compound is formed through the transfer of electrons between atoms. Anions, which are negatively charged ions, gain electrons from cations, which are positively charged ions. The attraction between the oppositely charged ions then holds the compound together in a crystal lattice structure. Without both anions and cations, there would be no transfer of electrons and therefore no formation of an ionic compound.

Explanation

In an ionic compound, both anions and cations must be present to form a molecule. This is because an ionic compound is formed through the transfer of electrons between atoms. Anions, which are negatively charged ions, gain electrons from cations, which are positively charged ions. The attraction between the oppositely charged ions then holds the compound together in a crystal lattice structure. Without both anions and cations, there would be no transfer of electrons and therefore no formation of an ionic compound.

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12. Elements are pure substances _________________

Elements are pure substances by definition. An element is a type of substance that cannot be broken down into simpler substances by chemical means. It consists of only one type of atom, which means it is chemically homogeneous and has a fixed composition. Therefore, elements are considered pure substances.

Explanation

Elements are pure substances by definition. An element is a type of substance that cannot be broken down into simpler substances by chemical means. It consists of only one type of atom, which means it is chemically homogeneous and has a fixed composition. Therefore, elements are considered pure substances.

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14. Electrons are responsible for chemical properties of an atom __________

Electrons are responsible for the chemical properties of an atom because they determine the atom's reactivity and ability to form chemical bonds. The number and arrangement of electrons in an atom's outermost energy level determine its valence electrons, which are involved in chemical reactions. These valence electrons determine how an atom will interact with other atoms to form compounds. Therefore, the presence and behavior of electrons play a crucial role in determining the chemical properties of an atom.

Explanation

Electrons are responsible for the chemical properties of an atom because they determine the atom's reactivity and ability to form chemical bonds. The number and arrangement of electrons in an atom's outermost energy level determine its valence electrons, which are involved in chemical reactions. These valence electrons determine how an atom will interact with other atoms to form compounds. Therefore, the presence and behavior of electrons play a crucial role in determining the chemical properties of an atom.

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15. The size of an atom increases when it obtains one or more electrons forming an ion. _______

When an atom gains one or more electrons to form an ion, the size of the atom increases. This is because the additional electrons are negatively charged and are attracted to the positively charged nucleus. As a result, the electron cloud surrounding the nucleus expands, causing the overall size of the atom to increase.

Explanation

When an atom gains one or more electrons to form an ion, the size of the atom increases. This is because the additional electrons are negatively charged and are attracted to the positively charged nucleus. As a result, the electron cloud surrounding the nucleus expands, causing the overall size of the atom to increase.

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16. The formula for the compound containing Al³⁺ and S^2- is Al₂S_{3 _______________}

The formula for the compound containing Al3+ and S2- is Al2S3 because aluminum (Al) has a 3+ charge and sulfur (S) has a 2- charge. In order to balance the charges, we need two aluminum ions (2 x 3+ = 6+) for every three sulfur ions (3 x 2- = 6-). Therefore, the formula is Al2S3.

Explanation

The formula for the compound containing Al3+ and S2- is Al2S3 because aluminum (Al) has a 3+ charge and sulfur (S) has a 2- charge. In order to balance the charges, we need two aluminum ions (2 x 3+ = 6+) for every three sulfur ions (3 x 2- = 6-). Therefore, the formula is Al2S3.

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17. The law of constant composition says that the composition of compounds changes according to the place of origin. __________________

The law of constant composition says that the composition of
compounds does not change regardless of to the place of origin)

Explanation

The law of constant composition says that the composition of
compounds does not change regardless of to the place of origin)

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18. The atomic number of an atom is the sum of the protons and neutrons present in the nucleus of that atom. ___________

The atomic number of an atom is the number of neutrons
present in the nucleus of that atom

Explanation

The atomic number of an atom is the number of neutrons
present in the nucleus of that atom

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